JP7243857B2 - Thermally conductive addition-curable silicone composition and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an addition-curable silicone composition having excellent thermal conductivity and a method for producing the same. The present invention relates to a thermally conductive addition-curable silicone composition that can be incorporated into electronic devices without damaging heat-generating electronic components such as the like, and that gives a cured thermally conductive silicone composition that is excellent in stress relaxation and insulation, and a method for producing the same. .

In recent years, the amount of heat generated from ICs and circuits has increased as electronic component circuits have become highly integrated and high-voltage, and thermally conductive silicone compositions have been used for the purpose of relieving thermal stress.
It is known that fillers with good thermal conductivity should be used for the purpose of relieving thermal stress. Examples of such fillers include silica powder, aluminum oxide powder, silicon carbide powder, and silicon nitride powder. , aluminum nitride powder, magnesium oxide powder, diamond powder, metal powder such as iron, stainless steel and copper, and carbon powder.

However, among the above fillers, metal powders and carbon powders are electrically conductive and cannot be used in thermally conductive silicone compositions intended for electrical insulation. Both silicon carbide powder and diamond powder are materials with high hardness, and wiring and elements in the substrate filled with these powders may be worn or cut. Silicon nitride powder, aluminum nitride powder, magnesium oxide powder, etc. can be used from the viewpoint of electrical insulation, but they all show hydrolysis, lack long-term stability, and are two-liquid thermal conductive addition curing. It was also difficult to ensure the storage stability of the mold silicone composition.

From the above point of view, fillers that can be used in practice include silica powder and aluminum oxide powder, but silica powder does not have sufficient thermal conductivity. Workability such as viscosity of the composition is greatly reduced. In addition, when aluminum oxide powder is used, it is known that due to the influence of Al-OH groups remaining on the surface of alumina, a dehydrogenation reaction occurs by reacting with hydrogen atoms bonded to silicon atoms, resulting in low cross-linking density. The influence of the dehydrogenation reaction cannot be ignored for the set low-hardness material. As a countermeasure, the use of aluminum oxide treated with a silyl ketene acetal or the like has been proposed (Patent No. 2741436: Patent Document 1), and a silicone gel composition that regulates the pH of aluminum oxide has been proposed (Patent No. No. 3676544: Patent Document 2).

However, the surface-treated aluminum oxide with the silyl ketene acetal is difficult to use in an environment where stress relaxation is the main purpose because there is a concern that the hardness will change with the passage of time. In addition, aluminum oxide having a specified pH uses an inorganic acid treatment agent, and the remaining inorganic acid causes a dehydrogenation reaction over time, making it difficult to suppress changes in hardness over time. rice field.

Therefore, thermally conductive silicone gel compositions with excellent fluidity and long-term storage stability, excellent stress relaxation properties after curing, and little change in hardness over time have been proposed. There is no description of a two-pack type thermally conductive addition-curable silicone composition, and the specified amount of Na ⁺ ions after boiling extraction of aluminum oxide is too large, so the thermal conductivity is 2.0 W/m· K or more was insufficient (Patent No. 5821160: Patent Document 3).

Japanese Patent No. 2741436 Japanese Patent No. 3676544 Japanese Patent No. 5821160

The present invention has been made in view of the above circumstances, and is capable of being applied to modules including electrical and electronic components and circuit boards on which these are mounted, and exhibiting excellent stress relaxation properties and thermal conductivity after curing. An object of the present invention is to provide a thermally conductive addition-curable silicone composition capable of

As a result of intensive studies to achieve the above object, the present inventors have found that an organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule and a hydrogen atom bonded to silicon atoms in one molecule. Aluminum oxide particles having at least 3 organohydrogenpolysiloxanes and an aluminum oxide powder having a Na ⁺ ion content of 50 ppm or less when the aqueous layer is measured by ion chromatography by heating and extracting aluminum oxide powder with pure water at 60° C. for 24 hours. wherein said aluminum oxide particles are surface-treated with said organohydrogenpolysiloxane, and said organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms per molecule. A thermally conductive addition-curable silicone composition containing siloxane and a platinum group metal catalyst, preferably as a thermally conductive filler, is extracted by heating aluminum oxide powder with pure water at 60° C. for 24 hours, and the water layer is Aluminum oxide having a Na ⁺ ion content of 50 ppm or less as measured by ion chromatography, an alkenyl group-containing organopolysiloxane, and an organohydrogenpolysiloxane are simultaneously heat-treated and mixed at a temperature of 70° C. or higher, and then the mixture is obtained. A thermally conductive addition-curable silicone composition obtained by adding an organohydrogenpolysiloxane and a curing catalyst, or as a thermally conductive filler, heat extraction of aluminum oxide powder with pure water at 60 ° C. for 24 hours. , Aluminum oxide having an amount of Na ⁺ ions of 50 ppm or less when the water layer is measured by ion chromatography, and an alkenyl group-containing organopolysiloxane are heat-treated and mixed at a temperature of 70 ° C. or higher, and then the mixture is cured. The amount of Na ⁺ ions is 50 ppm when the aluminum oxide powder is heated and extracted with the first solution to which the catalyst is added and pure water at 60 ° C. for 24 hours as a thermally conductive filler, and the aqueous layer is measured by ion chromatography. After the following aluminum oxide, alkenyl group-containing organopolysiloxane, and organohydrogenpolysiloxane having a specific structure are simultaneously heat-treated and mixed at a temperature of 70° C. or higher, the organohydrogenpolysiloxane having a specific structure is added to the mixture. By using a thermally conductive addition-curable silicone composition consisting of a 2-part type with a 2nd part to be added, it was found that storage stability is improved and changes in hardness over time are suppressed. Arrived.

（５）
（式中、Ｒ⁴は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁵は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｇは５～１００の整数であり、ｈは１～３の整数である。）
で表され、２５℃における粘度が０．０１～３０Ｐａ・ｓのオルガノポリシロキサン（Ｇ）との温度７０℃以上の加熱処理混合物である［２］又は［３］に記載の熱伝導性付加硬化型シリコーン組成物。
［５］
（Ａ）下記平均組成式（１）
Ｒ_aＲ¹ _bＳｉＯ_(4-a-b)/2 （１）
（式中、Ｒは独立にアルケニル基であり、Ｒ¹は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ａは０．０００１～０．２、ｂは１．７～２．２で、かつａ＋ｂが１．９～２．４を満足する正数である。）
で表され、一分子中に珪素原子に結合したアルケニル基を少なくとも２個有するオルガノポリシロキサン：１００質量部、
（Ｂ）下記平均組成式（２）
Ｒ² _cＨ_dＳｉＯ_(4-c-d)/2 （２）
（式中、Ｒ²は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ｃは０．７～２．２、ｄは０．００１～０．５で、かつｃ＋ｄが０．８～２．５を満足する正数である。）
で表され、一分子中に珪素原子に結合した水素原子を少なくとも３個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分中のアルケニル基１個に対し（Ｂ）成分中の珪素原子結合水素原子（ＳｉＨ基）が０．１～２個となる量、
（Ｃ）６０℃×２４時間純水で酸化アルミニウム粉末を加熱抽出し、その水層をイオンクロマトグラフィーで測定した場合のＮａ⁺イオン量が５０ｐｐｍ以下の酸化アルミニウム：１，０００～７，０００質量部
を７０℃以上の温度で加熱処理を行い、冷却した加熱処理混合物に、
（Ｄ）下記平均組成式（３）
Ｒ³ _eＨ_fＳｉＯ_(4-e-f)/2 （３）
（式中、Ｒ³は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ｅは０．７～２．２、ｆは０．００１～０．５で、かつｅ＋ｆが０．８～２．５を満足する正数である。）
で表され、一分子中に珪素原子に結合した水素原子を少なくとも２個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分中のアルケニル基１個に対し（Ｄ）成分中の珪素原子結合水素原子（ＳｉＨ基）が０．０１～３個となる量、及び
（Ｅ）白金族金属触媒：（Ａ）成分に対して白金族金属質量で１～２００ｐｐｍ
を添加混合することにより、得られる組成物の熱伝導率がＩＳＯ ２２００７－２準拠のホットディスク法において、２．０～７．０Ｗ／ｍ・Ｋであり、得られる組成物の２５℃における粘度がスパイラル粘度計によるローターＡ、回転数１０ｒｐｍ測定時（ずり速度６（１／ｓｅｃ））において、３０～８００Ｐａ・ｓである熱伝導性付加硬化型シリコーン組成物の製造方法。
［６］
（Ｂ）成分と（Ｄ）成分中のＳｉＨ基の合計量が、（Ａ）成分中のアルケニル基１個に対して０．１１～５個の割合である［５］に記載の熱伝導性付加硬化型シリコーン組成物の製造方法。
［７］
（Ａ）～（Ｃ）成分に、更にシランカップリング剤（Ｆ）及び／又は下記一般式（５）

（５）
（式中、Ｒ⁴は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁵は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｇは５～１００の整数であり、ｈは１～３の整数である。）
で表され、２５℃における粘度が０．０１～３０Ｐａ・ｓのオルガノポリシロキサン（Ｇ）を混合して加熱処理を行う［５］又は［６］に記載の熱伝導性付加硬化型シリコーン組成物の製造方法。
［８］
（Ａ）下記平均組成式（１）
Ｒ_aＲ¹ _bＳｉＯ_(4-a-b)/2 （１）
（式中、Ｒは独立にアルケニル基であり、Ｒ¹は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ａは０．０００１～０．２、ｂは１．７～２．２で、かつａ＋ｂが１．９～２．４を満足する正数である。）
で表され、一分子中に珪素原子に結合したアルケニル基を少なくとも２個有するオルガノポリシロキサン、及び
（Ｃ）６０℃×２４時間純水で酸化アルミニウム粉末を加熱抽出し、その水層をイオンクロマトグラフィーで測定した場合のＮａ⁺イオン量が５０ｐｐｍ以下の酸化アルミニウム
の温度７０℃以上の加熱処理混合物と、
（Ｅ）白金族金属触媒：（Ａ）成分の合計質量に対して白金族金属質量で１～２００ｐｐｍと
を含有する第１液と、
（Ａ）下記平均組成式（１）
Ｒ_aＲ¹ _bＳｉＯ_(4-a-b)/2 （１）
（式中、Ｒは独立にアルケニル基であり、Ｒ¹は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ａは０．０００１～０．２、ｂは１．７～２．２で、かつａ＋ｂが１．９～２．４を満足する正数である。）
で表され、一分子中に珪素原子に結合したアルケニル基を少なくとも２個有するオルガノポリシロキサン、
（Ｂ）下記平均組成式（２）
Ｒ² _cＨ_dＳｉＯ_(4-c-d)/2 （２）
（式中、Ｒ²は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ｃは０．７～２．２、ｄは０．００１～０．５で、かつｃ＋ｄが０．８～２．５を満足する正数である。）
で表され、一分子中に珪素原子に結合した水素原子を少なくとも３個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分の合計中のアルケニル基１個に対し（Ｂ）成分中の珪素原子結合水素原子（ＳｉＨ基）が０．１～２個となる量、及び
（Ｃ）６０℃×２４時間純水で酸化アルミニウム粉末を加熱抽出し、その水層をイオンクロマトグラフィーで測定した場合のＮａ⁺イオン量が５０ｐｐｍ以下の酸化アルミニウム
の温度７０℃以上の加熱処理混合物と、
（Ｈ）下記平均組成式（４）
Ｒ⁷ _jＨ_kＳｉＯ_(4-j-k)/2 （４）
（式中、Ｒ⁷は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ｊは０．７～２．２、ｋは０．００１～０．５で、かつｊ＋ｋが０．８～２．５を満足する正数である。）
で表され、一分子中に珪素原子に結合した水素原子を２個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分の合計中のアルケニル基１個に対し（Ｈ）成分中の珪素原子結合水素原子（ＳｉＨ基）が０．０１～３個となる量と
を含有する第２液と
の２液型からなり、但し、第１液は上記（Ｂ）、（Ｈ）成分を含有せず、第２液は上記（Ｅ）成分を含有せず、組成物中の（Ａ）成分の合計は１００質量部であり、（Ｃ）成分の合計は１，０００～７，０００質量部であり、第１液及び第２液それぞれの熱伝導率がＩＳＯ ２２００７－２準拠のホットディスク法において、２．０～７．０Ｗ／ｍ・Ｋであり、第１液及び第２液それぞれの２５℃における粘度がスパイラル粘度計によるローターＡ、回転数１０ｒｐｍ測定時（ずり速度６（１／ｓｅｃ））において、３０～８００Ｐａ・ｓである［１］に記載の熱伝導性付加硬化型シリコーン組成物。
［９］
（Ｂ）成分と（Ｈ）成分中のＳｉＨ基の合計量が、（Ａ）成分の合計中のアルケニル基１個に対して０．１１～５個の割合である［８］に記載の熱伝導性付加硬化型シリコーン組成物。
［１０］
更にシランカップリング剤（Ｆ）及び／又は下記一般式（５）

（５）
（式中、Ｒ⁴は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁵は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｇは５～１００の整数であり、ｈは１～３の整数である。）
で表され、２５℃における粘度が０．０１～３０Ｐａ・ｓのオルガノポリシロキサン（Ｇ）を、第１液に（Ａ）、（Ｃ）成分との温度７０℃以上の加熱処理混合物として、第２液に（Ａ）、（Ｂ）、（Ｃ）成分との温度７０℃以上の加熱処理混合物として含有する［８］又は［９］に記載の熱伝導性付加硬化型シリコーン組成物。
［１１］
（Ａ）下記平均組成式（１）
Ｒ_aＲ¹ _bＳｉＯ_(4-a-b)/2 （１）
（式中、Ｒは独立にアルケニル基であり、Ｒ¹は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ａは０．０００１～０．２、ｂは１．７～２．２で、かつａ＋ｂが１．９～２．４を満足する正数である。）
で表され、一分子中に珪素原子に結合したアルケニル基を少なくとも２個有するオルガノポリシロキサン、及び
（Ｃ）６０℃×２４時間純水で酸化アルミニウム粉末を加熱抽出し、その水層をイオンクロマトグラフィーで測定した場合のＮａ⁺イオン量が５０ｐｐｍ以下の酸化アルミニウム
を７０℃以上の温度で混合して加熱処理を行い、冷却した加熱処理混合物に、
（Ｅ）白金族金属触媒：（Ａ）成分の合計質量に対して白金族金属質量で１～２００ｐｐｍ
を添加混合することにより、第１液を調製する工程、
（Ａ）下記平均組成式（１）
Ｒ_aＲ¹ _bＳｉＯ_(4-a-b)/2 （１）
（式中、Ｒは独立にアルケニル基であり、Ｒ¹は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ａは０．０００１～０．２、ｂは１．７～２．２で、かつａ＋ｂが１．９～２．４を満足する正数である。）
で表され、一分子中に珪素原子に結合したアルケニル基を少なくとも２個有するオルガノポリシロキサン、
（Ｂ）下記平均組成式（２）
Ｒ² _cＨ_dＳｉＯ_(4-c-d)/2 （２）
（式中、Ｒ²は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ｃは０．７～２．２、ｄは０．００１～０．５で、かつｃ＋ｄが０．８～２．５を満足する正数である。）
で表され、一分子中に珪素原子に結合した水素原子を少なくとも３個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分の合計中のアルケニル基１個に対し（Ｂ）成分中の珪素原子結合水素原子（ＳｉＨ基）が０．１～２個となる量、及び
（Ｃ）６０℃×２４時間純水で酸化アルミニウム粉末を加熱抽出し、その水層をイオンクロマトグラフィーで測定した場合のＮａ⁺イオン量が５０ｐｐｍ以下の酸化アルミニウム
を７０℃以上の温度で混合して加熱処理を行い、冷却した加熱処理混合物に、
（Ｈ）下記平均組成式（４）
Ｒ⁷ _jＨ_kＳｉＯ_(4-j-k)/2 （４）
（式中、Ｒ⁷は独立に脂肪族不飽和結合を有さない非置換又は置換の１価炭化水素基であり、ｊは０．７～２．２、ｋは０．００１～０．５で、かつｊ＋ｋが０．８～２．５を満足する正数である。）
で表され、一分子中に珪素原子に結合した水素原子を２個有するオルガノハイドロジェンポリシロキサン：（Ａ）成分の合計中のアルケニル基１個に対し（Ｈ）成分中の珪素原子結合水素原子（ＳｉＨ基）が０．０１～３個となる量
を混合することにより、第２液を調製する工程
を有し、但し、第１液は（Ｂ）、（Ｈ）成分を、第２液は（Ｅ）成分を含有しないものであり、組成物中の（Ａ）成分の合計は１００質量部であり、（Ｃ）成分の合計は１，０００～７，０００質量部であり、得られる第１液及び第２液それぞれの熱伝導率がＩＳＯ ２２００７－２準拠のホットディスク法において、２．０～７．０Ｗ／ｍ・Ｋであり、得られる第１液及び第２液それぞれの２５℃における粘度がスパイラル粘度計によるローターＡ、回転数１０ｒｐｍ測定時（ずり速度６（１／ｓｅｃ））において、３０～８００Ｐａ・ｓである熱伝導性付加硬化型シリコーン組成物の製造方法。
［１２］
（Ｂ）成分と（Ｈ）成分中のＳｉＨ基の合計量が、（Ａ）成分の合計中のアルケニル基１個に対して０．１１～５個の割合である［１１］に記載の熱伝導性付加硬化型シリコーン組成物の製造方法。
［１３］
更にシランカップリング剤（Ｆ）及び／又は下記一般式（５）

（５）
（式中、Ｒ⁴は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁵は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｇは５～１００の整数であり、ｈは１～３の整数である。）
で表され、２５℃における粘度が０．０１～３０Ｐａ・ｓのオルガノポリシロキサン（Ｇ）を、第１液の（Ａ）、（Ｃ）成分と、第２液の（Ａ）、（Ｂ）、（Ｃ）成分に混合して加熱処理を行う［１１］又は［１２］に記載の熱伝導性付加硬化型シリコーン組成物の製造方法。Accordingly, the present invention provides the following thermally conductive addition-curable silicone composition and method for producing the same.
[1]
Organopolysiloxane having at least two silicon-bonded alkenyl groups in one molecule and organohydrogenpolysiloxane having at least three silicon-bonded hydrogen atoms in one molecule, and purified at 60°C for 24 hours Aluminum oxide powder is heated and extracted with water, and the aqueous layer is a heated mixture with aluminum oxide particles having a Na ⁺ ion content of 50 ppm or less when measured by ion chromatography, wherein the aluminum oxide particles are the organohydrogen. a mixture surface-treated with polysiloxane;
an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule;
A thermally conductive addition-curable silicone composition containing a platinum group metal catalyst.
[2]
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane represented by and having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (B) ( SiH group) is 0.1 to 2,
(C) Aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60°C for 24 hours and the water layer is measured by ion chromatography: 1,000 to 7,000 mass A heat-treated mixture having a temperature of 70 ° C. or higher in the part,
(D) the following average composition formula (3)
^R3eHfSiO _{(4-ef)/2 ( 3} )
(wherein R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, e is 0.7 to 2.2, f is 0.001 to 0.5 and e+f is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (D) ( SiH group) is 0.01 to 3, and (E) platinum group metal catalyst: 1 to 200 ppm in terms of mass of platinum group metal relative to component (A)
In the hot disk method in accordance with ISO 22007-2, the thermal conductivity of the composition is 2.0 to 7.0 W / m K, and the viscosity of the composition at 25 ° C. is determined by a spiral viscometer. The thermally conductive addition-curable silicone composition according to [1], which is 30 to 800 Pa·s when measured at a rotational speed of 10 rpm (shear rate of 6 (1/sec)).
[3]
Thermal conductivity according to [2], wherein the total amount of SiH groups in components (B) and (D) is 0.11 to 5 per alkenyl group in component (A) Addition-curable silicone composition.
[4]
The heat-treated mixture contains components (A) to (C), a silane coupling agent (F) and/or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
and is a heat-treated mixture at a temperature of 70 ° C. or higher with an organopolysiloxane (G) having a viscosity of 0.01 to 30 Pa s at 25 ° C. Thermally conductive addition curing according to [2] or [3] mold silicone composition.
[5]
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane represented by and having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (B) ( SiH group) is 0.1 to 2,
(C) Aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60°C for 24 hours and the water layer is measured by ion chromatography: 1,000 to 7,000 mass Part is heat-treated at a temperature of 70 ° C. or higher, and the cooled heat-treated mixture is
(D) the following average composition formula (3)
^R3eHfSiO _{(4-ef)/2 ( 3} )
(wherein R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, e is 0.7 to 2.2, f is 0.001 to 0.5 and e+f is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (D) ( SiH group) is 0.01 to 3, and (E) platinum group metal catalyst: 1 to 200 ppm in terms of mass of platinum group metal relative to component (A)
By adding and mixing, the thermal conductivity of the resulting composition is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the viscosity of the resulting composition at 25 ° C. is 30 to 800 Pa·s when measured with a spiral viscometer at a rotor A rotation speed of 10 rpm (shear rate 6 (1/sec)).
[6]
Thermal conductivity according to [5], wherein the total amount of SiH groups in components (B) and (D) is 0.11 to 5 per alkenyl group in component (A) A method for producing an addition-curable silicone composition.
[7]
In addition to components (A) to (C), a silane coupling agent (F) and / or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
The thermally conductive addition-curable silicone composition according to [5] or [6], wherein an organopolysiloxane (G) having a viscosity at 25° C. of 0.01 to 30 Pa·s is mixed and heat-treated. manufacturing method.
[8]
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
and (C) heat-extracting aluminum oxide powder with pure water at 60° C. for 24 hours, and subjecting the water layer to ion chromatography. a heat-treated mixture at a temperature of 70° C. or higher of aluminum oxide having a Na ⁺ ion content of 50 ppm or less as measured graphically;
(E) a platinum group metal catalyst: a first liquid containing 1 to 200 ppm by mass of platinum group metal relative to the total mass of component (A);
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, represented by
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms per molecule represented by the formula: Silicon-bonded hydrogen in component (B) per alkenyl group in the total of component (A) and (C) the Na ⁺ obtained by heat-extracting the aluminum oxide powder with pure water at 60° C. for 24 hours and measuring the water layer by ion chromatography. A heat-treated mixture of aluminum oxide having an ion content of 50 ppm or less at a temperature of 70 ° C. or higher;
(H) Average composition formula (4) below
^R7jHkSiO ₍ 4 _{- jk)/2} (4)
(wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, j is 0.7 to 2.2, k is 0.001 to 0.5 and j+k is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having two silicon-bonded hydrogen atoms in one molecule represented by: per alkenyl group in the total of component (A), a silicon-bonded hydrogen atom in component (H) (SiH groups) in an amount of 0.01 to 3, and a second liquid containing 0.01 to 3 groups, provided that the first liquid does not contain the above components (B) and (H), and the second liquid does not contain the above components (B) and (H). Liquid 2 does not contain the above component (E), the total amount of component (A) in the composition is 100 parts by mass, the total amount of component (C) is 1,000 to 7,000 parts by mass, The thermal conductivity of each of liquid 1 and liquid 2 is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the viscosity of each liquid 1 and 2 at 25 ° C. is 30 to 800 Pa·s when measured with a spiral viscometer at a rotor A rotation speed of 10 rpm (shear rate 6 (1/sec)).
[9]
The heat according to [8], wherein the total amount of SiH groups in components (B) and (H) is 0.11 to 5 per alkenyl group in the total of components (A). A conductive addition-curable silicone composition.
[10]
Furthermore, a silane coupling agent (F) and / or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
represented by, and the viscosity at 25 ° C. of 0.01 ~ 30 Pa s organopolysiloxane (G), the first component (A), (C) as a heat-treated mixture at a temperature of 70 ° C. or higher with the first component, the second The thermally conductive addition-curable silicone composition according to [8] or [9], which contains components (A), (B), and (C) as a heat-treated mixture at a temperature of 70° C. or higher in the two components.
[11]
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
and (C) heat-extracting aluminum oxide powder with pure water at 60° C. for 24 hours, and subjecting the water layer to ion chromatography. Aluminum oxide having an amount of Na ⁺ ions of 50 ppm or less as measured graphically is mixed at a temperature of 70° C. or higher and heat-treated, and the cooled heat-treated mixture is mixed with
(E) platinum group metal catalyst: 1 to 200 ppm in platinum group metal mass with respect to the total mass of component (A)
A step of preparing the first liquid by adding and mixing
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, represented by
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms per molecule represented by the formula: Silicon-bonded hydrogen in component (B) per alkenyl group in the total of component (A) and (C) the Na ⁺ obtained by heat-extracting the aluminum oxide powder with pure water at 60° C. for 24 hours and measuring the water layer by ion chromatography. Aluminum oxide having an ion amount of 50 ppm or less is mixed at a temperature of 70 ° C. or higher and heat-treated, and the cooled heat-treated mixture is
(H) Average composition formula (4) below
^R7jHkSiO ₍ 4 _{- jk)/2} (4)
(wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, j is 0.7 to 2.2, k is 0.001 to 0.5 and j+k is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having two silicon-bonded hydrogen atoms in one molecule represented by: per alkenyl group in the total of component (A), a silicon-bonded hydrogen atom in component (H) A step of preparing a second liquid by mixing an amount of (SiH groups) of 0.01 to 3, provided that the first liquid contains components (B) and (H), and the second liquid does not contain the (E) component, the total of the (A) component in the composition is 100 parts by mass, the total of the (C) component is 1,000 to 7,000 parts by mass, and obtained The thermal conductivity of each of the first and second liquids is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the obtained first and second liquids each have a thermal conductivity of 25 A method for producing a thermally conductive addition-curable silicone composition having a viscosity of 30 to 800 Pa·s at °C when measured with a spiral viscometer at a rotor A rotation speed of 10 rpm (a shear rate of 6 (1/sec)).
[12]
The heat according to [11], wherein the total amount of SiH groups in components (B) and (H) is 0.11 to 5 per alkenyl group in the total of components (A). A method for producing a conductive addition-curable silicone composition.
[13]
Furthermore, a silane coupling agent (F) and / or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
and an organopolysiloxane (G) having a viscosity of 0.01 to 30 Pa s at 25 ° C., components (A) and (C) of the first liquid, and components (A) and (B) of the second liquid. , The method for producing a thermally conductive addition-curable silicone composition according to [11] or [12], wherein the composition is mixed with component (C) and heat-treated.

According to the present invention, it is possible to obtain a thermally conductive addition-curable silicone composition that has improved storage stability and suppresses changes in hardness over time. Since it can be suitably used to protect electronic parts and circuit boards on which these are mounted, it can exhibit excellent stress relaxation properties and thermal conductivity.

The present invention will be described in detail below.
The thermally conductive addition-curable silicone composition of the present invention comprises an organopolysiloxane having at least two silicon-bonded alkenyl groups per molecule and at least three silicon-bonded hydrogen atoms per molecule. and the aluminum oxide powder having an Na ⁺ ion content of 50 ppm or less when the aqueous layer is measured by ion chromatography after heating and extracting the aluminum oxide powder with pure water at 60°C for 24 hours. a mixture in which the aluminum oxide particles are surface-treated with the organohydrogenpolysiloxane;
an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms in one molecule;
and a platinum group metal catalyst.

[First embodiment]
As the thermally conductive addition-curable silicone composition of the first embodiment of the present invention,
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane represented by and having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (B) ( SiH group) is 0.1 to 2,
(C) Aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60°C for 24 hours and the water layer is measured by ion chromatography: 1,000 to 7,000 mass A heat-treated mixture having a temperature of 70 ° C. or higher in the part,
(D) the following average composition formula (3)
^R3eHfSiO _{(4-ef)/2 ( 3} )
(wherein R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, e is 0.7 to 2.2, f is 0.001 to 0.5 and e+f is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (D) ( SiH group) is 0.01 to 3, and (E) platinum group metal catalyst: 1 to 200 ppm in terms of mass of platinum group metal relative to component (A)
In the hot disk method in accordance with ISO 22007-2, the thermal conductivity of the composition is 2.0 to 7.0 W / m K, and the viscosity of the composition at 25 ° C. is determined by a spiral viscometer. When measured at a rotational speed of 10 rpm (shear rate of 6 (1/sec)), it is 30 to 800 Pa·s.

The (A) component of the composition of the present invention is a component that serves as the main ingredient (base polymer) of the composition. Component (A) is an organopolysiloxane represented by the following average compositional formula (1) and having at least two silicon-bonded alkenyl groups (hereinafter referred to as "silicon-bonded alkenyl groups") per molecule. . At least two silicon-bonded alkenyl groups are present in one molecule, preferably 2 to 50, more preferably 2 to 20. These silicon atom-bonded alkenyl groups may be bonded to the silicon atom at the terminal of the molecular chain, bonded to the silicon atom at the non-terminal of the molecular chain (that is, other than the terminal of the molecular chain), or a combination thereof. may
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)

In the above formula (1), each R is independently an alkenyl group usually having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples thereof include lower alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group and isobutenyl group, with vinyl group being particularly preferred.

In the above formula (1), R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group usually having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and having no aliphatic unsaturated bonds. . Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, octyl, and decyl; phenyl; , an aryl group such as a tolyl group; an aralkyl group such as a benzyl group and a phenylethyl group; A 3,3,3-trifluoropropyl group and the like can be mentioned, and a methyl group, a phenyl group and a 3,3,3-trifluoropropyl group are preferable from the viewpoint of ease of synthesis.

In the above formula (1), a is a positive number of 0.0001 to 0.2, preferably a positive number of 0.0005 to 0.1, b is a positive number of 1.7 to 2.2 is preferably a positive number of 1.9 to 2.0, a + b is a positive number satisfying 1.9 to 2.4, and a positive number satisfying 1.95 to 2.05 is preferred.

The molecular structure of the component (A) organopolysiloxane is not particularly limited, and is linear; part of the molecular chain includes RSiO _3/2 units, R ¹ SiO _3/2 units, and SiO ₂ units (in the formula, R and the group represented by R ¹ are as defined above); cyclic; three-dimensional network (resinous); Particularly preferred is a straight-chain diorganopolysiloxane consisting of repeating diorganosiloxane units and having both ends of the molecular chain blocked with triorganosiloxy groups.

The viscosity of the component (A) organopolysiloxane is preferably 50 to 100,000 mPa·s, more preferably 100 to 10,000 mPa·s. When this viscosity is from 50 to 100,000 mPa·s, the resulting cured product has excellent strength, fluidity and workability. The viscosity is a value at 25° C. measured by a rotational viscometer (same below).

（１Ａ）
（式中、Ｒ⁶は、独立に非置換又は置換の１価炭化水素基であり、但しＲ⁶の少なくとも２個はアルケニル基であり、ｉは２０～２，０００の整数である。）
で表されるものが挙げられる。As the organopolysiloxane of the component (A) that satisfies the above requirements, for example, the following general formula (1A):

(1A)
(In the formula, R ⁶ is independently an unsubstituted or substituted monovalent hydrocarbon group, provided that at least two of R ⁶ are alkenyl groups, and i is an integer of 20 to 2,000.)
Those represented by are mentioned.

In this formula (1A), the unsubstituted or substituted monovalent hydrocarbon group represented by R ⁶ is the above R (alkenyl group) and R ¹ (unsubstituted or substituted having no aliphatic unsaturated bond) monovalent hydrocarbon group), and the number of carbon atoms, specific examples, etc. are also the same. However, at least two, preferably 2 to 50, more preferably 2 to 20, R ⁶ are alkenyl groups. Also, i is preferably an integer of 40 to 1,200, more preferably 50 to 600.

Specific examples of the organopolysiloxane represented by the above formula (1A) include dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer having both molecular chain ends blocked with trimethylsiloxy groups, and molecular Dimethylsiloxane/methylvinylsiloxane copolymer with one chain end trimethylsiloxy group/one end dimethylvinylsiloxy group blocked, dimethylsiloxane/methylvinylsiloxane copolymer with both molecular chain ends blocked with dimethylvinylsiloxy group, dimethylvinylsiloxy at both molecular chain ends Examples include group-blocked dimethylsiloxane/diphenylsiloxane copolymers.

The (A) component organopolysiloxane may be used alone or in combination of two or more.
The above-mentioned organopolysiloxane having alkenyl groups is known per se and produced by a conventionally known method.

Component (B) of the composition of the present invention has at least three hydrogen atoms bonded to silicon atoms in one molecule, and acts as a surface treating agent and cross-linking agent for aluminum oxide, component (C). It is. That is, during the heat treatment at a high temperature, component (B) is partly consumed by a dehydrogenation reaction with the Al—OH groups remaining on the surface of component (C), inorganic acid surface treatment agent residues, and remaining silicon. A hydrogen atom bonded to the atom undergoes an addition reaction with the alkenyl group in component (A), and is an essential component of the present invention.

The component (B) is an organohydrogen represented by the following average compositional formula (2) and having at least three silicon-bonded hydrogen atoms (hereinafter also referred to as "silicon-bonded hydrogen atoms") per molecule. Polysiloxane. The number of silicon-bonded hydrogen atoms in one molecule of this organohydrogenpolysiloxane is preferably 3 to 100, more preferably 3 to 50, particularly preferably 3 to 20.
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)

In the above formula (2), R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. is. Specific examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups. Aryl groups such as phenyl, tolyl, xylyl and naphthyl groups; Aralkyl groups such as benzyl, phenylethyl and phenylpropyl; , 3,3,3-trifluoropropyl groups substituted with halogen atoms such as chlorine and bromine. Among them, alkyl group, aryl group and 3,3,3-trifluoropropyl group are preferred, and methyl group, phenyl group and 3,3,3-trifluoropropyl group are more preferred.

In the above formula (2), c is a positive number of 0.7 to 2.2, preferably a positive number of 1.0 to 2.1. d is a positive number of 0.001 to 0.5, preferably a positive number of 0.005 to 0.1. c+d is a positive number satisfying 0.8 to 2.5, preferably a positive number satisfying 1.0 to 2.5, and a positive number satisfying 1.5 to 2.2 is more preferred.

The number of silicon atoms in one molecule of component (B) organohydrogenpolysiloxane (that is, the degree of polymerization) is usually 10 to 1,000. The number is preferably 20 to 500, more preferably 20 to 100, from the viewpoint of good properties.

The molecular structure of the organohydrogenpolysiloxane of component (B) is not particularly limited as long as it satisfies the above requirements.

The viscosity of the component (B) organohydrogenpolysiloxane is generally 1 to 10,000 mPa·s, preferably 3 to 2,000 mPa·s, and more preferably 10 to 1,000 mPa·s. °C) is desirable.

Examples of the organohydrogenpolysiloxane represented by the above formula (2) include, for example, a methylhydrogensiloxane/dimethylsiloxane cyclic copolymer, a dimethylhydrogensiloxy-terminated methylhydrogen-dimethylsiloxane copolymer, dimethylhydrogensiloxy-terminated methylhydrogen-diphenylsiloxane copolymer at both molecular chain ends, dimethylhydrogensiloxy-terminated methylhydrogen at both molecular chain ends・Dimethylsiloxane-diphenylsiloxane copolymer, trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both molecular chain ends, dimethylsiloxane-methylhydrogensiloxane copolymer with trimethylsiloxy group-blocked at both molecular chain ends, trimethylsiloxy group at both molecular chain ends Blocked methylhydrogensiloxane/diphenylsiloxane copolymer, methylhydrogensiloxane/diphenylsiloxane/dimethylsiloxane copolymer blocked with trimethylsiloxy groups at both molecular chain ends, ( _CH3 )2HSiO1 _{/2 units} and ( _CH3 ) ₂ A copolymer consisting of SiO units and _{CH3SiO3 /2 units} , ( _CH3 ) _{2HSiO1 /2} units, ( _C6H5 ) _2SiO units, ( _CH3 ) _2SiO units and _{CH3SiO3 /} Copolymers consisting of _two units, ( _CH3 )( _C6H5 )HSiO1 _{/2 units} , ( _CH3 ) _2SiO units and _{CH3SiO3 /} 2 units, ( _CH3 ) ₂ A copolymer consisting of HSiO _1/2 units, (CH ₃ ) ₂ SiO units and C ₆ H ₅ SiO _3/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ )HSiO _1/2 units and (CH ₃ ) (CF ₃ C ₂ H ₄ ) SiO units and CH ₃ SiO _3/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ ) HSiO _1/2 units and (CH ₃ )(CF _3C2H4 )SiO units, ( _CH3 ) _{2SiO units and CH3SiO3/2 units ,} ( _{CH3 ) 2HSiO1/ 2 units} and ( _CH3 )( _{CF3C 2} H ₄ ) Copolymer of SiO units and CH ₃ SiO _3/2 units, (CH ₃ ) ₂ Copolymers of HSiO _1/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ )SiO units, (CH ₃ ) ₂ SiO units and CH ₃ SiO _3/2 units, (CH ₃ ) ₂ HSiO _{1 /2} units, (CH ₃ )(CF ₃ C ₂ H ₄ ) SiO units, (CH ₃ ) ₂ SiO units and (CF ₃ C ₂ H ₄ ) SiO _3/2 units. .

The (B) component organohydrogenpolysiloxane may be used alone or in combination of two or more.
Also, this organohydrogenpolysiloxane is synthesized by a conventionally known method.

The amount of component (B) organohydrogenpolysiloxane to be blended is 0.1 to 2 silicon-bonded hydrogen atoms (SiH groups) in component (B) per alkenyl group in component (A). The amount is preferably 0.2 to 2, more preferably 0.5 to 2. If the amount is too small, the effect of improving the storage stability may be insufficient, and if the amount is too large, the physical properties of the resulting thermally conductive cured product may become unstable.

The component (C) of the composition of the present invention is aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60° C. for 24 hours, and the aqueous layer is measured by ion chromatography. is.

The amount of Na ⁺ ions is 50 ppm or less, more preferably 30 ppm or less, when the aluminum oxide powder is heated and extracted with pure water at 60° C. for 24 hours and the aqueous layer is measured by ion chromatography. If the amount of Na ⁺ ions exceeds 50 ppm, the component (E) may deactivate over time.
Here, in order to make the amount of Na ⁺ ions in the aluminum oxide used in the present invention within the above range, commercially available aluminum oxide powder is dispersed in water and heated to room temperature (1 to 25° C.), or in order to shorten the process time, For example, the amount of Na ⁺ ions can be adjusted by washing with water by heating to 60° C. and stirring.

The aluminum oxide powder preferably has an average particle size of 1 to 100 μm, more preferably 5 to 50 μm, as measured by a laser diffraction method, and the shape of the particles is preferably crushed particles or rounded particles. Particles or spherical particles, preferably crushed particles and spherical particles. One type may be used alone, or two or more types having different average particle sizes may be used in combination within the range that does not impair the present invention. If the average particle size is less than 1 μm, the contact between the particles is reduced, and the thermal conductivity tends to deteriorate due to the increase in the contact thermal resistance between the particles. On the other hand, if the average particle size exceeds 100 μm, the unevenness of the surface of the sheet increases, the interfacial thermal resistance increases, and the thermal conductivity tends to deteriorate.

The thermally conductive filler of component (C) is 1,000 to 7,000 parts by mass, preferably 1,000 to 6,900 parts by mass, more preferably 1,000 parts by mass per 100 parts by mass of component (A). ~6,700 parts by mass. When the amount is within the above range, the thermally conductive addition-curable silicone composition gives the cured thermally conductive silicone composition of the present invention that has viscosity, thermal conductivity, storage stability, and hardness change over time can be suppressed. be able to.

In the present invention, these components (A) to (C) are heated to 70° C. or higher, preferably 100 to 200° C., more preferably 100 to 170° C., still more preferably 100 to 160° C., particularly preferably 100 to 150° C. and preferably for 60 minutes or more to obtain a heat-treated mixture of components (A) to (C). The upper limit of the heat treatment time is not particularly limited, but the heat treatment is preferably performed for 60 to 240 minutes, more preferably 60 to 180 minutes, and particularly preferably 60 to 120 minutes. If the heat treatment temperature is less than 70° C., the hydrogen atoms bonded to the silicon atoms in the component (B) and the reactive groups such as Al—OH groups and residual inorganic acids in the component (C) that can reduce the storage stability, If the reaction with the reactive substance progresses slowly and the heat treatment temperature is higher than 200° C., the polymers of component (A) and component (B) themselves may deteriorate. On the other hand, if the heat treatment time is too short, hydrogen atoms bonded to silicon atoms in the component (B), reactive groups such as Al—OH groups in the component (C), residual inorganic acid, and the like deteriorate the storage stability. In some cases, the reaction with the reactive group or reactive substance does not proceed sufficiently, resulting in an insufficient storage stability improvement effect.

Component (D) of the composition of the present invention has the following average composition formula (3)
^R3eHfSiO _{(4-ef)/2 ( 3} )
(wherein R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, e is 0.7 to 2.2, f is 0.001 to 0.5 and e+f is a positive number that satisfies 0.8 to 2.5.)
It is an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule. The number of silicon-bonded hydrogen atoms in one molecule of this organohydrogenpolysiloxane is preferably 2 to 100, more preferably 2 to 50, particularly preferably 2 to 20.

In the above formula (3), R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. is. Specific examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups. Aryl groups such as phenyl, tolyl, xylyl and naphthyl groups; Aralkyl groups such as benzyl, phenylethyl and phenylpropyl; , 3,3,3-trifluoropropyl groups substituted with halogen atoms such as chlorine and bromine. Among them, alkyl group, aryl group and 3,3,3-trifluoropropyl group are preferred, and methyl group, phenyl group and 3,3,3-trifluoropropyl group are more preferred.

In the above formula (3), e is a positive number of 0.7 to 2.2, preferably a positive number of 1.0 to 2.1. f is a positive number of 0.001 to 0.5, preferably a positive number of 0.005 to 0.1. e+f is a positive number satisfying 0.8 to 2.5, preferably a positive number satisfying 1.0 to 2.5, and a positive number satisfying 1.5 to 2.2 is more preferred.

The number of silicon atoms in one molecule of component (D) organohydrogenpolysiloxane (that is, the degree of polymerization) is usually 10 to 1,000. The number is preferably 15 to 500, more preferably 18 to 100, from the viewpoint of good properties.

Also, the molecular structure of the organohydrogenpolysiloxane of component (D) is not particularly limited as long as it satisfies the above requirements.

The viscosity of the component (D) organohydrogenpolysiloxane is usually 1 to 10,000 mPa·s, preferably 3 to 2,000 mPa·s, more preferably 10 to 1,000 mPa·s. °C) is desirable.

The organohydrogenpolysiloxane represented by the formula (3) includes, for example, a methylhydrogensiloxane/dimethylsiloxane cyclic copolymer, a methylhydrogenpolysiloxane having both molecular chain ends blocked with dimethylhydrogensiloxy groups, Dimethylhydrogensiloxy-terminated dimethylpolysiloxane, dimethylhydrogensiloxy-terminated methylhydrogen-dimethylsiloxane copolymer at both molecular chain ends, methylhydrogen-diphenylsiloxane copolymer with dimethylhydrogensiloxy-terminated ends at both molecular chain ends , methylhydrogen-dimethylsiloxane-diphenylsiloxane copolymer with dimethylhydrogensiloxy group-blocked at both molecular chain ends, methylhydrogenpolysiloxane with trimethylsiloxy group-blocked at both molecular chain ends, dimethylsiloxane-methyl with trimethylsiloxy group-blocked at both molecular chain ends Hydrogensiloxane copolymer, trimethylsiloxy group-blocked methylhydrogensiloxane/diphenylsiloxane copolymer at both molecular chain ends, methylhydrogensiloxane/diphenylsiloxane/dimethylsiloxane copolymer with trimethylsiloxy group-blocked at both molecular chain ends, (CH ₃ ) a copolymer consisting of ₂ HSiO _1/2 units, (CH ₃ ) ₂ SiO units and CH ₃ SiO _3/2 units, (CH ₃ ) ₂ HSiO _1/2 units and (C ₆ H ₅ ) ₂ SiO units; and ( _CH3 ) _2SiO units and _{CH3SiO3 /} 2 units, _{( CH3} ) _{( C6H5} )HSiO1 _/2 units, ( _CH3 ) _2SiO units and _{CH3SiO3 /2} units, ( _CH3 )2HSiO1 _{/ 2} units, ( _CH3 ) _2SiO units and _{C6H5SiO3 /2 units} , ( _CH3 )( _CF3 ) ( _C2H4 ) _{HSiO1 /2} units, _{(CH3)(CF3C2H4 ) SiO units and CH3SiO3 /2} units, ( _CH3 )( _CF3C2H ) ₄ ) Copolymers of HSiO _1/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ )SiO units, (CH ₃ ) ₂ SiO units and CH ₃ SiO _3/2 units, (CH ₃ ) ₂ HSiO _1/2 units and (CH ₃ )(CF ₃ C ₂ H ₄ )SiO a copolymer consisting of units and _{CH3SiO3 /2} units, ( _CH3 )2HSiO1 _{/2 units ,} ( _CH3 )( _CF3C2H4 )SiO units and ( _CH3 ) _2SiO units _; a copolymer consisting of _{CH3SiO3 /2} units, ( _CH3 )2HSiO1 _{/2 units ,} ( _CH3 )( _CF3C2H4 )SiO units, ( _CH3 ) _2SiO units and ( _{CF 3} C ₂ H ₄ ) SiO _3/2 units.

The (D) component organohydrogenpolysiloxane may be used alone or in combination of two or more.
Also, this organohydrogenpolysiloxane is synthesized by a conventionally known method.

The component (D) is represented by the above formula (3), but the same component as the component (B) may be exemplified. In other words, the component (B) may be exactly the same as component (B) or may have a different structure or degree of polymerization. Component (B) is used as a surface treatment agent for component (C), while component (D) reacts with the alkenyl groups in component (A) and is used as a cross-linking agent to obtain a cured product. be.

Therefore, the amount of component (D) used is 0.01 to 3, preferably 0.05 to 2 SiH groups in component (D) per alkenyl group in component (A), and more The amount is preferably 0.2 to 1.5. If the number of SiH groups in component (D) is less than 0.01 per alkenyl group in component (A), the silicone may become too soft and a stable cured silicone product may not be obtained. If the number of SiH groups in component exceeds 3 per alkenyl group in component (A), the cured silicone product may become too hard and brittle.

In the present invention, the total amount of SiH groups in components (B) and (D) described above is 0.11 to 5, particularly 0.25 to 1 alkenyl group in component (A). It is preferable to use it so that it may become four ratios. If the total number of SiH groups in components (B) and (D) is less than 0.11 for each alkenyl group in component (A), the cured silicone product will be too soft and stable. If the total number of SiH groups in components (B) and (D) exceeds 5 per alkenyl group in component (A), the cured silicone product becomes too hard. can become brittle.

The (E) component of the composition of the present invention is a platinum group metal catalyst, which promotes the addition reaction between the alkenyl groups in the (A) component and the silicon-bonded hydrogen atoms in the (B) and (D) components. It is a catalyst that For example, chloroplatinic acid, alcohol-modified chloroplatinic acid, coordination compounds of chloroplatinic acid and olefins, aldehydes, vinylsiloxanes, or acetylene compounds, tetrakis(triphenylphosphine)palladium, chlorotris(triphenylphosphine)rhodium etc. are used, preferably a platinum catalyst, most preferably a coordination compound of chloroplatinic acid and vinyl siloxane.

The amount of component (E) may be a catalytic amount, which is generally 1 to 200 ppm, preferably 2 to 100 ppm, in terms of mass of the platinum group metal relative to component (A). It is preferable to set the amount of the component (E) within this range because appropriate curability can be obtained.

(F) A silane coupling agent can be used in the composition of the present invention, if necessary. Examples of the (F) silane coupling agent include vinyl silane coupling agents, epoxy silane coupling agents, acrylic silane coupling agents, and long-chain alkyl silane coupling agents. Alternatively, two or more of them can be used in appropriate combination. Among them, a long-chain alkyl-based silane coupling agent is preferred, and decyltrimethoxysilane is preferred.

In the present invention, when component (F) is used, it is preferable to form a heat-treated mixture together with components (A) to (C) described above at a temperature of 70° C. or higher. It can also be pre-processed. In this case, the method for surface treatment of component (C) with component (F) includes a spraying method using a fluid nozzle, a stirring method with shear force, a dry method such as a ball mill or mixer, and a wet method such as a water-based or organic solvent-based method. Law can be adopted. Stirring is carried out to such an extent that the spherical aluminum oxide powder is not destroyed. The temperature in the system in the dry method or the drying temperature after the treatment is appropriately determined according to the type of the surface treatment agent within a range in which the surface treatment agent does not volatilize or decompose, and is 80 to 180°C.

When component (F) is used, the amount used is preferably 0.1 to 5 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of component (C). If the amount is less than 0.1 part by mass, the effect of lowering the viscosity is small, and if the amount is more than 5 parts by mass, the effect suitable for the amount used is not exhibited.

（５）
（式中、Ｒ⁴は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁵は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｇは５～１００の整数であり、ｈは１～３の整数である。）The composition of the present invention optionally contains (G) at least one hydrolyzable silyl group represented by the following general formula (5) per molecule, and has a viscosity of 0.01 at 25°C. Organopolysiloxanes with ˜30 Pa·s can be used.

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)

In the above formula (5), R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group having preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 3 carbon atoms, and Examples include straight chain alkyl groups, branched chain alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, aralkyl groups, halogenated alkyl groups. Examples of linear alkyl groups include methyl, ethyl, propyl, hexyl, octyl, and decyl groups. Branched chain alkyl groups include, for example, isopropyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group and the like. Cyclic alkyl groups include, for example, a cyclopentyl group and a cyclohexyl group. Examples of alkenyl groups include vinyl groups and allyl groups. Aryl groups include, for example, a phenyl group and a tolyl group. The aralkyl group includes, for example, 2-phenylethyl group, 2-methyl-2-phenylethyl group and the like. Examples of halogenated alkyl groups include 3,3,3-trifluoropropyl group, 2-(nonafluorobutyl)ethyl group, 2-(heptadecafluorooctyl)ethyl group and the like. R ⁴ is preferably a methyl group or a phenyl group.

In formula (5) above, R ⁵ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group. Examples of alkyl groups include straight-chain alkyl groups, branched-chain alkyl groups, and cyclic alkyl groups similar to those exemplified for R ⁴ . The alkoxyalkyl group includes, for example, a methoxyethyl group, a methoxypropyl group and the like, and those having 2 to 10 carbon atoms are preferred. Examples of the alkenyl group include those exemplified for R above, and those having 1 to 8 carbon atoms are preferred. The acyl group includes, for example, an acetyl group and an octanoyl group, and those having 2 to 10 carbon atoms are preferred. R ⁵ is preferably an alkyl group, particularly preferably a methyl group or an ethyl group.

In the above formula (5), g is an integer of 5-100, preferably 8-50, and h is an integer of 1-3, preferably 3.

（式中、Ｍｅはメチル基である。以下、同じ。）Preferred specific examples of the (G) component organopolysiloxane include the following.

(In the formula, Me is a methyl group. The same shall apply hereinafter.)

The viscosity of the component (G) organopolysiloxane at 25° C. is usually 0.01 to 30 Pa·s, preferably 0.01 to 10 Pa·s. If the viscosity is lower than 0.01 Pa·s, the oil of component (G) may easily bleed from the silicone composition. If the viscosity is higher than 30 Pa·s, the fluidity of the resulting silicone composition will be significantly poor, possibly deteriorating the workability of application.

When component (G) is used, the blending amount is preferably 5 to 900 parts by mass, more preferably 10 to 900 parts by mass, still more preferably 15 to 700 parts by mass, per 100 parts by mass of component (A). If the amount of component (G) is less than 5 parts by mass, the effect of lowering the viscosity is small. There is

When the component (G) is blended, the component (G) is blended together with the components (A) to (C) and heat-treated at a temperature of 70° C. or higher to form a cooled heat-treated mixture. It is preferable to mix the (D) and (E) components.

In addition to the components (A) to (G) described above as other compounding agents, the composition of the present invention may contain various known additives as long as they do not impair the object of the present invention. .
For example, reaction control agents for adjusting the curing speed and storage stability, specifically triallyl isocyanate alkyl maleate, acetylene alcohols such as ethynylcyclohexanol and their silanes, modified siloxanes; hydroperoxide, tetra Methylethylenediamine, benzotriazole, etc., ferrous oxide, ferric oxide, etc. as colorants, either alone or in combination, and fumed silica, etc. as a thixotropic agent, can be blended. The blending amount of each of these is preferably 0.01 to 100,000 ppm in terms of mass per composition.

The composition of the present invention is a heat-treated mixture obtained by heating and mixing the above-described components (A) to (C) and, if necessary, components (F) and (G) at 70 ° C. or higher, preferably at 0 to 50 ° C., or more. It is preferably cooled to room temperature (1 to 25° C.), and the above components (D) and (E) and, if necessary, other ingredients are added and uniformly mixed.

The thermal conductivity of the composition of the present invention is 2.0 to 7.0 W/m K, preferably 2.2 to 7.0 W/m K, according to the hot disk method in accordance with ISO 22007-2. be. If the thermal conductivity is too low, the heat dissipation performance of the heat-generating electronic component may become insufficient. In the present invention, the thermal conductivity can be set within the range specified above, particularly by adjusting the blending amount of the component (C) within the range specified above.

The viscosity of the composition of the present invention at 25° C. is 30 to 800 Pa·s, preferably 30 to 700 Pa·s, when measured with a spiral viscometer at rotor A and rotation speed 10 rpm (shear rate 6 (1/sec)). is s. If the viscosity is too low, the shape retention of the composition may be insufficient, and if it is too high, workability may become difficult. In the present invention, the viscosity within the above range can be achieved by adjusting the blending amount of the component (C) within the range specified above.

The curing conditions for the composition of the present invention obtained above may be the same as those for conventional thermally conductive addition-curable silicone compositions, such as heating or curing at room temperature. In the case of curing by heating, a temperature of 80° C. or higher is usually sufficient although it depends on the desired curing time.

The obtained cured product of the composition of the present invention preferably has a hardness in the range of 5 to 95, particularly 10 to 90, as determined by the Shore OO hardness tester specified in ASTM D 2240-05.

[Second embodiment]
As the thermally conductive addition-curable silicone composition of the second embodiment of the present invention,
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
and (C) heat-extracting aluminum oxide powder with pure water at 60° C. for 24 hours, and subjecting the water layer to ion chromatography. a heat-treated mixture at a temperature of 70° C. or higher of aluminum oxide having a Na ⁺ ion content of 50 ppm or less as measured graphically;
(E) a platinum group metal catalyst: a first liquid containing 1 to 200 ppm by mass of platinum group metal relative to the total mass of component (A);
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, represented by
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms per molecule represented by the formula: Silicon-bonded hydrogen in component (B) per alkenyl group in the total of component (A) and (C) the Na ⁺ obtained by heat-extracting the aluminum oxide powder with pure water at 60° C. for 24 hours and measuring the water layer by ion chromatography. A heat-treated mixture of aluminum oxide having an ion content of 50 ppm or less at a temperature of 70 ° C. or higher;
(H) Average composition formula (4) below
^R7jHkSiO ₍ 4 _{- jk)/2} (4)
(wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, j is 0.7 to 2.2, k is 0.001 to 0.5 and j+k is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having two silicon-bonded hydrogen atoms in one molecule represented by: per alkenyl group in the total of component (A), a silicon-bonded hydrogen atom in component (H) (SiH groups) in an amount of 0.01 to 3, and a second liquid containing 0.01 to 3 groups, provided that the first liquid does not contain the above components (B) and (H), and the second liquid does not contain the above components (B) and (H). Liquid 2 does not contain the above component (E), the total amount of component (A) in the composition is 100 parts by mass, the total amount of component (C) is 1,000 to 7,000 parts by mass, The thermal conductivity of each of liquid 1 and liquid 2 is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the viscosity of each liquid 1 and 2 at 25 ° C. is 30 to 800 Pa·s when measured with a spiral viscometer at rotor A and rotation speed of 10 rpm (shear rate of 6 (1/sec)).

The (A) component of the composition of the present invention is a component that serves as the main ingredient (base polymer) of the composition. Component (A) is an organopolysiloxane represented by the following average compositional formula (1) and having at least two alkenyl groups bonded to silicon atoms (hereinafter referred to as "silicon-bonded alkenyl groups") per molecule. . At least two silicon-bonded alkenyl groups are present in one molecule, preferably 2 to 50, more preferably 2 to 20. These silicon atom-bonded alkenyl groups may be bonded to the silicon atom at the terminal of the molecular chain, bonded to the silicon atom at the non-terminal of the molecular chain (that is, other than the terminal of the molecular chain), or a combination thereof. may
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)

In the above formula (1), each R is independently an alkenyl group usually having 2 to 6 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples thereof include lower alkenyl groups such as vinyl group, allyl group, propenyl group, isopropenyl group, butenyl group and isobutenyl group, with vinyl group being particularly preferred.

In the above formula (1), R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group usually having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and having no aliphatic unsaturated bonds. . Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, cyclohexyl, octyl, and decyl; phenyl; , an aryl group such as a tolyl group; an aralkyl group such as a benzyl group and a phenylethyl group; A 3,3,3-trifluoropropyl group and the like can be mentioned, and a methyl group, a phenyl group and a 3,3,3-trifluoropropyl group are preferable from the viewpoint of ease of synthesis.

In the above formula (1), a is a positive number of 0.0001 to 0.2, preferably a positive number of 0.0005 to 0.1, b is a positive number of 1.7 to 2.2 is preferably a positive number of 1.9 to 2.0, a + b is a positive number satisfying 1.9 to 2.4, and a positive number satisfying 1.95 to 2.05 is preferred.

The molecular structure of the component (A) organopolysiloxane is not particularly limited, and is linear; part of the molecular chain includes RSiO _3/2 units, R ¹ SiO _3/2 units, and SiO ₂ units (in the formula, R and the group represented by R ¹ are as defined above); cyclic; three-dimensional network (resinous); Particularly preferred is a straight-chain diorganopolysiloxane consisting of repeating diorganosiloxane units and having both ends of the molecular chain blocked with triorganosiloxy groups.

The viscosity of the component (A) organopolysiloxane is preferably 50 to 100,000 mPa·s, more preferably 100 to 10,000 mPa·s. When this viscosity is from 50 to 100,000 mPa·s, the resulting cured product has excellent strength, fluidity and workability. The viscosity is a value at 25° C. measured by a rotational viscometer (same below).

（１Ａ）
（式中、Ｒ⁶は、独立に非置換又は置換の１価炭化水素基であり、但しＲ⁶の少なくとも２個はアルケニル基であり、ｉは２０～２，０００の整数である。）
で表されるものが挙げられる。As the organopolysiloxane of the component (A) that satisfies the above requirements, for example, the following general formula (1A):

(1A)
(In the formula, R ⁶ is independently an unsubstituted or substituted monovalent hydrocarbon group, provided that at least two of R ⁶ are alkenyl groups, and i is an integer of 20 to 2,000.)
Those represented by are mentioned.

In this formula (1A), the unsubstituted or substituted monovalent hydrocarbon group represented by R ⁶ is the above R (alkenyl group) and R ¹ (unsubstituted or substituted having no aliphatic unsaturated bond) monovalent hydrocarbon group), and the number of carbon atoms, specific examples, etc. are also the same. However, at least two, preferably 2 to 50, more preferably 2 to 20, R ⁶ are alkenyl groups. Also, i is preferably an integer of 40 to 1,200, more preferably 50 to 600.

Specific examples of the organopolysiloxane represented by the above formula (1A) include dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymer having both molecular chain ends blocked with trimethylsiloxy groups, and molecular Dimethylsiloxane/methylvinylsiloxane copolymer with one chain end trimethylsiloxy group/one end dimethylvinylsiloxy group blocked, dimethylsiloxane/methylvinylsiloxane copolymer with both molecular chain ends blocked with dimethylvinylsiloxy group, dimethylvinylsiloxy at both molecular chain ends Examples include group-blocked dimethylsiloxane/diphenylsiloxane copolymers.

The (A) component organopolysiloxane may be used alone or in combination of two or more.
The above-mentioned organopolysiloxane having alkenyl groups is known per se and produced by a conventionally known method.

The component (A) is used in both the first liquid and the second liquid, and the ratio of the component (A) used in the first liquid and the second liquid is There is no particular limitation as long as the mixing ratio is used so that the mass ratio is substantially the same.

Component (B) of the composition of the present invention has at least three hydrogen atoms bonded to silicon atoms in one molecule, and serves as a surface treating agent and cross-linking agent for aluminum oxide, component (C) of the second liquid. It acts as an agent. That is, when the heat treatment is performed at a high temperature, the component (B) is partially consumed by a dehydrogenation reaction with the Al—OH groups remaining on the surface of the component (C) of the second liquid and the residue of the inorganic acid surface treatment agent. , the hydrogen atoms bonded to the remaining silicon atoms undergo an addition reaction with the alkenyl groups in all components (A) contained in the first liquid and the second liquid, and are an essential component of the present invention.

The component (B) is an organohydrogen represented by the following average composition formula (2) and having at least three silicon-bonded hydrogen atoms (hereinafter also referred to as "silicon-bonded hydrogen atoms") per molecule. Polysiloxane. The number of silicon-bonded hydrogen atoms in one molecule of this organohydrogenpolysiloxane is preferably 3 to 100, more preferably 3 to 50, particularly preferably 3 to 20. The hydrogen atoms bonded to the silicon atoms may be located at the ends of the molecular chain, in the middle of the molecular chain, or at both.
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)

In the above formula (2), R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. is. Specific examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups. Aryl groups such as phenyl, tolyl, xylyl and naphthyl groups; Aralkyl groups such as benzyl, phenylethyl and phenylpropyl; , 3,3,3-trifluoropropyl groups substituted with halogen atoms such as chlorine and bromine. Among them, alkyl group, aryl group and 3,3,3-trifluoropropyl group are preferred, and methyl group, phenyl group and 3,3,3-trifluoropropyl group are more preferred.

In the above formula (2), c is a positive number of 0.7 to 2.2, preferably a positive number of 1.0 to 2.1. d is a positive number of 0.001 to 0.5, preferably a positive number of 0.005 to 0.1. c+d is a positive number satisfying 0.8 to 2.5, preferably a positive number satisfying 1.0 to 2.5, and a positive number satisfying 1.5 to 2.2 is more preferred.

The number of silicon atoms in one molecule of component (B) organohydrogenpolysiloxane (that is, the degree of polymerization) is usually 10 to 1,000. The number is preferably 20 to 500, more preferably 20 to 100, from the viewpoint of good properties.

The molecular structure of the organohydrogenpolysiloxane of component (B) is not particularly limited as long as it satisfies the above requirements.

The viscosity of the component (B) organohydrogenpolysiloxane is generally 1 to 10,000 mPa·s, preferably 3 to 2,000 mPa·s, and more preferably 10 to 1,000 mPa·s. °C) is desirable.

Examples of the organohydrogenpolysiloxane represented by the above formula (2) include, for example, a methylhydrogensiloxane/dimethylsiloxane cyclic copolymer, a dimethylhydrogensiloxy-terminated methylhydrogen-dimethylsiloxane copolymer, dimethylhydrogensiloxy-terminated methylhydrogen-diphenylsiloxane copolymer at both molecular chain ends, dimethylhydrogensiloxy-terminated methylhydrogen at both molecular chain ends・Dimethylsiloxane-diphenylsiloxane copolymer, trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both molecular chain ends, dimethylsiloxane-methylhydrogensiloxane copolymer with trimethylsiloxy group-blocked at both molecular chain ends, trimethylsiloxy group at both molecular chain ends Blocked methylhydrogensiloxane/diphenylsiloxane copolymer, methylhydrogensiloxane/diphenylsiloxane/dimethylsiloxane copolymer blocked with trimethylsiloxy groups at both molecular chain ends, ( _CH3 )2HSiO1 _{/2 units} and ( _CH3 ) ₂ A copolymer consisting of SiO units and _{CH3SiO3 /2 units} , ( _CH3 ) _{2HSiO1 /2} units, ( _C6H5 ) _2SiO units, ( _CH3 ) _2SiO units and _{CH3SiO3 /} Copolymers consisting of _two units, ( _CH3 )( _C6H5 )HSiO1 _{/2 units} , ( _CH3 ) _2SiO units and _{CH3SiO3 /} 2 units, ( _CH3 ) ₂ A copolymer consisting of HSiO _1/2 units, (CH ₃ ) ₂ SiO units and C ₆ H ₅ SiO _3/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ )HSiO _1/2 units and (CH ₃ ) (CF ₃ C ₂ H ₄ ) SiO units and CH ₃ SiO _3/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ ) HSiO _1/2 units and (CH ₃ )(CF _3C2H4 )SiO units, ( _CH3 ) _{2SiO units and CH3SiO3/2 units ,} ( _{CH3 ) 2HSiO1/ 2 units} and ( _CH3 )( _{CF3C 2} H ₄ ) Copolymer of SiO units and CH ₃ SiO _3/2 units, (CH ₃ ) ₂ Copolymers of HSiO _1/2 units, (CH ₃ )(CF ₃ C ₂ H ₄ )SiO units, (CH ₃ ) ₂ SiO units and CH ₃ SiO _3/2 units, (CH ₃ ) ₂ HSiO _{1 /2} units, (CH ₃ )(CF ₃ C ₂ H ₄ ) SiO units, (CH ₃ ) ₂ SiO units and (CF ₃ C ₂ H ₄ ) SiO _3/2 units. .

The (B) component organohydrogenpolysiloxane may be used alone or in combination of two or more.
Also, this organohydrogenpolysiloxane is synthesized by a conventionally known method.

The amount of component (B) organohydrogenpolysiloxane to be blended is such that one alkenyl group in all components (A) contained in the first and second components is a silicon-bonded hydrogen atom ( SiH groups) is an amount that provides 0.1 to 2, preferably 0.1 to 1.8, more preferably 0.1 to 1.5. If the amount is too small, the effect of improving the storage stability may be insufficient, and if the amount is too large, the physical properties of the resulting thermally conductive cured product may become unstable.

The component (C) of the composition of the present invention is aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60° C. for 24 hours, and the aqueous layer is measured by ion chromatography. is.

The amount of Na ⁺ ions is 50 ppm or less, more preferably 30 ppm or less, when the aluminum oxide powder is heated and extracted with pure water at 60° C. for 24 hours and the aqueous layer is measured by ion chromatography. If the amount of Na ⁺ ions exceeds 50 ppm, the component (E) may deactivate over time.
Here, in order to make the amount of Na ⁺ ions in the aluminum oxide used in the present invention within the above range, commercially available aluminum oxide powder is dispersed in water and heated to room temperature (1 to 25° C.), or in order to shorten the process time, For example, the amount of Na ⁺ ions can be adjusted by washing with water by heating to 60° C. and stirring.

The aluminum oxide powder preferably has an average particle size of 1 to 100 μm, more preferably 1 to 80 μm, as measured by a laser diffraction method, and the shape of the particles is preferably crushed particles or rounded particles. Particles or spherical particles, preferably crushed particles and spherical particles. One type may be used alone, or two or more types having different average particle sizes may be used in combination within the range that does not impair the present invention. If the average particle size is less than 1 μm, the contact between the particles is reduced, and the thermal conductivity tends to deteriorate due to the increase in the contact thermal resistance between the particles. On the other hand, if the average particle size exceeds 100 μm, the unevenness of the surface of the sheet increases, the interfacial thermal resistance increases, and the thermal conductivity tends to deteriorate.

The amount of the thermally conductive filler of component (C) (total of component (C)) is 1,000 to 7,000 parts by mass, preferably 1,000 parts by mass, per 100 parts by mass of component (A). 6,900 parts by mass, more preferably 1,000 to 6,700 parts by mass. When the amount is within the above range, the thermally conductive addition-curable silicone composition gives the cured thermally conductive silicone composition of the present invention that has viscosity, thermal conductivity, storage stability, and hardness change over time can be suppressed. be able to.

In addition, the component (C) is used in both the first liquid and the second liquid, and the ratio of the component (C) used in the first liquid and the second liquid is There is no particular limitation as long as the mixing ratio is used so that the mass ratio is substantially the same.

The (H) component of the composition of the present invention has the following average composition formula (4)
^R7jHkSiO ₍ 4 _{- jk)/2} (4)
(wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, j is 0.7 to 2.2, k is 0.001 to 0.5 and j+k is a positive number that satisfies 0.8 to 2.5.)
It is an organohydrogenpolysiloxane having two silicon-bonded hydrogen atoms in one molecule.

In the above formula (4), R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and usually has 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms. is. Specific examples include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, and decyl groups. Aryl groups such as phenyl, tolyl, xylyl and naphthyl groups; Aralkyl groups such as benzyl, phenylethyl and phenylpropyl; , 3,3,3-trifluoropropyl groups substituted with halogen atoms such as chlorine and bromine. Among them, alkyl group, aryl group and 3,3,3-trifluoropropyl group are preferred, and methyl group, phenyl group and 3,3,3-trifluoropropyl group are more preferred.

In the above formula (4), j is a positive number of 0.7 to 2.2, preferably a positive number of 1.0 to 2.1. k is a positive number of 0.001 to 0.5, preferably a positive number of 0.005 to 0.1. j+k is a positive number satisfying 0.8 to 2.5, preferably a positive number satisfying 1.0 to 2.5, and a positive number satisfying 1.5 to 2.2 is more preferred.

The (H) component organohydrogenpolysiloxane has two silicon-bonded hydrogen atoms in one molecule, whether at the end of the molecular chain or in the middle of the molecular chain. , and both of which may have one each, but preferably at the ends of the molecular chains.
The number of silicon atoms in one molecule of component (H) organohydrogenpolysiloxane (that is, the degree of polymerization) is usually 10 to 1,000. The number is preferably 15 to 500, more preferably 18 to 100, from the viewpoint of good properties.

The molecular structure of the organohydrogenpolysiloxane of component (H) is not particularly limited as long as it satisfies the above requirements.

The viscosity of the component (H) organohydrogenpolysiloxane is usually 1 to 10,000 mPa·s, preferably 3 to 2,000 mPa·s, and more preferably 10 to 1,000 mPa·s. °C) is desirable.

Examples of the organohydrogenpolysiloxane represented by the above formula (4) include a methylhydrogensiloxane/dimethylsiloxane cyclic copolymer, a dimethylpolysiloxane blocked at both ends of the molecular chain with dimethylhydrogensiloxy groups, and trimethyl at both ends of the molecular chain. Siloxy group-blocked methylhydrogenpolysiloxane, both molecular chain ends trimethylsiloxy group-blocked dimethylsiloxane/methylhydrogensiloxane copolymer, molecular chain both ends trimethylsiloxy group-blocked methylhydrogensiloxane/diphenylsiloxane copolymer, both molecular chain ends Terminal trimethylsiloxy group-blocked methylhydrogensiloxane/diphenylsiloxane/dimethylsiloxane copolymer, copolymer consisting of ( _CH3 )2HSiO1 _{/ 2} units, ( _CH3 ) _2SiO units and _{CH3SiO3 /} 2 units , ( _CH3 )2HSiO1 _{/ 2} units, ( _C6H5 ) _2SiO units, _{( CH3} ) _2SiO units and _{CH3SiO3 /2 units ; H 5} ) HSiO _{1/2 units , (CH 3 ) 2 SiO} units and CH ₃ SiO _3/2 units _{; A} copolymer consisting of _{6H5SiO3 /2 units} , ( _CH3 )( _{CF3C2H4 )} HSiO1 _/2 units and ( _CH3 ) _{( CF3C2H4} )SiO units _{and CH3SiO 3/2} units, _{( CH3} )( _CF3C2H4 ) _{HSiO1 /2} units and ( _CH3 )( _{CF3C2H4 )} SiO units _and ( _CH3 ) _{2SiO a} copolymer consisting of units and _{CH3SiO3 /2} units, ( _CH3 ) _{2HSiO1 /2} units, ( _CH3 )( _CF3C2H4 )SiO units and _{CH3SiO3 /2} units _; ( _CH3 ) _{2HSiO1 / 2} units, ( _CH3 )( _CF3C2H4 )SiO units _, ( _CH3 ) _2SiO units and _{CH3SiO3 /2} units Copolymer, ( _CH3 )2HSiO1 _{/ 2 units and (CH3)(CF3C2H4 ) SiO units} and ( _CH3 ) _2SiO units and ( _CF3C2H4 ) _{SiO3 /2} units, and the like.

The (H) component organohydrogenpolysiloxane may be used alone or in combination of two or more.
Also, this organohydrogenpolysiloxane is synthesized by a conventionally known method.

Here, the (H) component has two hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule, and at least three hydrogen atoms bonded to silicon atoms in one molecule (B ) component in this respect. In addition, the (B) component is also used as a surface treatment agent for the (C) component of the second liquid, while the (H) component is It is used as a cross-linking agent to react with alkenyl groups to obtain a cured product. That is, since the component (H) has two SiH groups, if even one is deactivated, the three-dimensional cross-linking will not occur. Therefore, in the present invention, the component (C) of the second liquid is surface-treated with the above-described component (B) so that the component (H) blended in the second liquid does not deteriorate over time.

Therefore, the amount of component (H) used is 0.01 to 3 SiH groups in component (H) per alkenyl group in all components (A) contained in the first liquid and the second liquid. , preferably 0.05 to 2, more preferably 0.2 to 1.5. If the number of SiH groups in component (H) is less than 0.01 per alkenyl group in component (A), the silicone may become too soft and a stable cured silicone product may not be obtained. If the number of SiH groups in component exceeds 3 per alkenyl group in component (A), the cured silicone product may become too hard and brittle.

In the present invention, the total amount of SiH groups in the above components (B) and (H) is 0 per alkenyl group in all components (A) contained in the first liquid and the second liquid. 0.11 to 5, particularly preferably 0.25 to 4. If the total number of SiH groups in components (B) and (H) is less than 0.11 per alkenyl group in component (A), the silicone will be too soft and a stable cured product will be obtained. If the total number of SiH groups in components (B) and (H) exceeds 5 per alkenyl group in component (A), the cured silicone product will become too hard. can become brittle.

The (E) component of the composition of the present invention is a platinum group metal catalyst, and the alkenyl groups in the (A) component (all (A) components contained in the first and second liquids) and the (B) component and ( H) is a catalyst that promotes the addition reaction of hydrogen atoms bonded to silicon atoms in the component. For example, chloroplatinic acid, alcohol-modified chloroplatinic acid, coordination compounds of chloroplatinic acid and olefins, aldehydes, vinylsiloxanes, or acetylene compounds, tetrakis(triphenylphosphine)palladium, chlorotris(triphenylphosphine)rhodium etc. are used, preferably a platinum catalyst, most preferably a coordination compound of chloroplatinic acid and vinyl siloxane.

The amount of component (E) may be a catalytic amount, which is generally 1 to 200 ppm, preferably 2 to 100 ppm, in terms of mass of the platinum group metal relative to the total mass of component (A). It is preferable to set the amount of the component (E) within this range because appropriate curability can be obtained.

(F) A silane coupling agent can be used in the composition of the present invention, if necessary. By blending the component (F), the effect of lowering the viscosity of the first liquid and the second liquid can be obtained. Examples of the (F) silane coupling agent include vinyl silane coupling agents, epoxy silane coupling agents, acrylic silane coupling agents, and long-chain alkyl silane coupling agents. Alternatively, two or more of them can be used in appropriate combination. Among them, a long-chain alkyl-based silane coupling agent is preferred, and decyltrimethoxysilane is preferred.

In the present invention, when component (F) is used, a heat-treated mixture is heated at a temperature of 70 ° C. or higher together with components (A) and (C) of the first liquid or components (A) to (C) of the second liquid. However, it is also possible to pretreat the (C) component with the (F) component. In this case, the method for surface treatment of component (C) with component (F) includes a spraying method using a fluid nozzle, a stirring method with shear force, a dry method such as a ball mill or mixer, and a wet method such as a water-based or organic solvent-based method. Law can be adopted. Stirring is carried out to such an extent that the spherical aluminum oxide powder is not destroyed. The temperature in the system in the dry method or the drying temperature after the treatment is appropriately determined according to the type of the surface treatment agent within a range in which the surface treatment agent does not volatilize or decompose, and is 80 to 180°C.

When component (F) is used, the amount used is preferably 0.1 to 5 parts by mass, more preferably 1 to 5 parts by mass, per 100 parts by mass of component (C). If the amount is less than 0.1 part by mass, the effect of lowering the viscosity is small, and if the amount is more than 5 parts by mass, the effect suitable for the amount used is not exhibited.

In addition, when the component (F) is used, it is used in both the first liquid and the second liquid, and the ratio of the component (F) used in the first liquid and the second liquid is not particularly limited. For example, the same amount can be blended in the first liquid and the second liquid.

（５）
（式中、Ｒ⁴は独立に非置換又は置換の１価炭化水素基であり、Ｒ⁵は独立にアルキル基、アルコキシアルキル基、アルケニル基又はアシル基であり、ｇは５～１００の整数であり、ｈは１～３の整数である。）The composition of the present invention optionally contains (G) at least one hydrolyzable silyl group represented by the following general formula (5) per molecule, and has a viscosity at 25° C. of 0.01. Organopolysiloxanes with ˜30 Pa·s can be used. By blending the component (G), the effect of lowering the viscosity of the first liquid and the second liquid can be obtained.

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)

In the above formula (5), R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group having preferably 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 3 carbon atoms, and Examples include straight chain alkyl groups, branched chain alkyl groups, cyclic alkyl groups, alkenyl groups, aryl groups, aralkyl groups, halogenated alkyl groups. Examples of linear alkyl groups include methyl, ethyl, propyl, hexyl, octyl, and decyl groups. Branched chain alkyl groups include, for example, isopropyl group, isobutyl group, tert-butyl group, 2-ethylhexyl group and the like. Cyclic alkyl groups include, for example, a cyclopentyl group and a cyclohexyl group. Examples of alkenyl groups include vinyl groups and allyl groups. Aryl groups include, for example, a phenyl group and a tolyl group. The aralkyl group includes, for example, 2-phenylethyl group, 2-methyl-2-phenylethyl group and the like. Examples of halogenated alkyl groups include 3,3,3-trifluoropropyl group, 2-(nonafluorobutyl)ethyl group, 2-(heptadecafluorooctyl)ethyl group and the like. R ⁴ is preferably a methyl group or a phenyl group.

In formula (5) above, R ⁵ is independently an alkyl group, an alkoxyalkyl group, an alkenyl group or an acyl group. Examples of alkyl groups include straight-chain alkyl groups, branched-chain alkyl groups, and cyclic alkyl groups similar to those exemplified for R ⁴ . The alkoxyalkyl group includes, for example, methoxyethyl group, methoxypropyl group and the like, and those having 2 to 10 carbon atoms are preferable. Examples of the alkenyl group include those exemplified for R above, and those having 1 to 8 carbon atoms are preferred. The acyl group includes, for example, an acetyl group and an octanoyl group, and those having 2 to 10 carbon atoms are preferred. R ⁵ is preferably an alkyl group, particularly preferably a methyl group or an ethyl group.

In the above formula (5), g is an integer of 5-100, preferably 8-50, and h is an integer of 1-3, preferably 3.

（式中、Ｍｅはメチル基である。以下、同じ。）Preferred specific examples of the (G) component organopolysiloxane include the following.

(In the formula, Me is a methyl group. The same shall apply hereinafter.)

The viscosity of the component (G) organopolysiloxane at 25° C. is usually 0.01 to 30 Pa·s, preferably 0.01 to 10 Pa·s. If the viscosity is lower than 0.01 Pa·s, the oil of component (G) may easily bleed from the silicone composition. If the viscosity is higher than 30 Pa·s, the fluidity of the resulting silicone composition will be significantly poor, possibly deteriorating the workability of application.

When component (G) is used, the blending amount is preferably 5 to 900 parts by mass, more preferably 10 to 900 parts by mass, and even more preferably 15 to 700 parts by mass based on 100 parts by mass of component (A). If the amount of component (G) is less than 5 parts by mass, the effect of lowering the viscosity is small. There is

When the component (G) is used, it is used in both the first liquid and the second liquid, and the ratio of the component (G) used in the first liquid and the second liquid is not particularly limited. For example, the same amount can be blended in the first liquid and the second liquid.

In addition, when the (G) component is blended, the (G) component is blended with the (A) and (C) components of the first liquid described above or the (A) to (C) components of the second liquid, and 70 It is preferable that the component (E) or the component (H) is blended after the heat treatment is performed at a temperature of 10° C. or higher to form a cooled heat-treated mixture.

In the composition of the present invention, in addition to the components (A) to (C) and (E) to (H) described above as other compounding agents, various known ingredients may be added to the extent that the object of the present invention is not impaired. of additives can be blended.

For example, reaction control agents for adjusting the curing speed and storage stability, specifically triallyl isocyanate alkyl maleate, acetylene alcohols such as ethynylcyclohexanol and their silanes, modified siloxanes; hydroperoxide, tetra Methylethylenediamine, benzotriazole, etc., ferrous oxide, ferric oxide, etc. as colorants, either alone or in combination, and fumed silica, etc. as a thixotropic agent, can be blended. The blending amount of each of these is preferably 0.01 to 100,000 ppm in terms of mass per composition.

The composition of the present invention contains the above components (A) to (C), (E), (H), and optionally the above components (F), (G) and other components, a first liquid and a second liquid.
Here, the first liquid contains a heat-treated mixture of components (A) and (C) and, if necessary, components (F) and (G) at a temperature of 70 ° C. or higher, and component (E), and (B ) and (H) components, and the second liquid is a heat treatment of components (A), (B), (C) and, if necessary, components (F) and (G) at a temperature of 70 ° C. or higher. It contains a mixture, component (H) and, if necessary, other additives, and does not contain component (E).

[First liquid]
The first liquid contains the above components (A) and (C), and if necessary, a heat-treated mixture of the components (F) and (G) at a temperature of 70 ° C. or higher, and the above component (E), and the above (B ) and component (H).
The heat-treated mixture is prepared by heating the above components (A) and (C) and, if necessary, (F) and (G) to 70° C. or higher, preferably 100 to 200° C., more preferably 100 to 170° C., still more preferably are mixed under heating at 100 to 160° C., particularly preferably 100 to 150° C., preferably for 60 minutes or longer. The upper limit of the heat treatment time is not particularly limited, but the heat treatment is preferably performed for 60 to 240 minutes, more preferably 60 to 180 minutes, and particularly preferably 60 to 120 minutes. When the heat treatment temperature is less than 70°C, the surface treatment of component (C) by component (A) may be insufficient. ) components may decompose. On the other hand, if the heat treatment time is too short, the surface treatment of component (C) by component (A) may be insufficient.
Components (A) and (C) obtained above and, if necessary, components (F) and (G) are mixed and heated at 70°C or higher, and the heat-treated mixture is preferably heated to 0 to 50°C, more preferably After cooling to room temperature (1 to 25° C.), the above component (E) is added and mixed uniformly. Here, the heat-treated mixture and the component (E) are mixed under normal temperature (1 to 25° C.) for about 5 to 30 minutes, and the first liquid can be obtained by the above method.

[Second liquid]
The second liquid is a heat-treated mixture of the above components (A), (B), (C) and optionally (F) and (G) at a temperature of 70 ° C. or higher, the above component (H), and optionally It contains other additives and does not contain the above component (E).
The heat-treated mixture is prepared by heating the above components (A), (B), (C) and, if necessary, (F) and (G) to 70°C or higher, preferably 100 to 200°C, more preferably 100 to 170°C. C., more preferably 100 to 160.degree. C., particularly preferably 100 to 150.degree. C., for preferably 60 minutes or more. The upper limit of the heat treatment time is not particularly limited, but the heat treatment is preferably performed for 60 to 240 minutes, more preferably 60 to 180 minutes, and particularly preferably 60 to 120 minutes. If the heat treatment temperature is less than 70° C., the hydrogen atoms bonded to the silicon atoms in the component (B) and the reactive groups such as Al—OH groups and residual inorganic acids in the component (C) that can reduce the storage stability, If the reaction with the reactive substance progresses slowly and the heat treatment temperature is higher than 200° C., the polymers of component (A) and component (B) themselves may deteriorate. On the other hand, if the heat treatment time is too short, hydrogen atoms bonded to silicon atoms in the component (B), reactive groups such as Al—OH groups in the component (C), residual inorganic acid, and the like deteriorate the storage stability. In some cases, the reaction with the reactive group or reactive substance does not proceed sufficiently, resulting in an insufficient storage stability improvement effect.
Components (A), (B), and (C) obtained above, and if necessary, components (F) and (G) are mixed and the heat-treated mixture heated at 70°C or higher is preferably heated to 0 to 50°C. , more preferably cooled to normal temperature (1 to 25°C), the above component (H) and, if necessary, other additives are added and mixed uniformly. Here, the heat-treated mixture, component (H), and other additives if necessary are mixed under conditions of room temperature (1 to 25°C) for about 5 to 30 minutes, and the second solution is obtained by the above method. be able to.

As a mixing device for preparing the first liquid and the second liquid, known mixers such as a static mixer, a planetary mixer, and a paddle mixer can be used.

In the composition of the present invention, the thermal conductivities of the first liquid and the second liquid are each 2.0 to 7.0 W/m·K, preferably 2.0 to 7.0 W/m·K, according to ISO 22007-2 compliant hot disk method. 2 to 7.0 W/m·K. If the thermal conductivity is too low, the heat dissipation performance of the heat-generating electronic component may become insufficient. In the present invention, the thermal conductivity can be set within the range specified above, particularly by adjusting the blending amount of the component (C) within the range specified above.

In the composition of the present invention, the viscosities of the first liquid and the second liquid at 25 ° C. are measured by a spiral viscometer at a rotor A and a rotation speed of 10 rpm (shear rate 6 (1 / sec)), respectively, 30 to 800 Pa · s, preferably 30 to 700 Pa·s. If the viscosity is too low, the shape retention of the composition may be insufficient, and if it is too high, workability may become difficult. In the present invention, the viscosity within the above range can be achieved by adjusting the blending amount of the component (C) within the range specified above.

In the composition of the present invention, the first liquid and the second liquid have a small difference in viscosity, and can be uniformly mixed by a static mixer such as a static mixer. In this case, when measuring the rotor A with a spiral viscometer at a rotation speed of 10 rpm (shear rate 6 (1 / sec)), the initial viscosity difference between the first liquid and the second liquid at 25 ° C. (at the time of preparation) is the first It is preferably ±0 to 80%, particularly ±0 to 50%, based on the viscosity of the liquid.

In the composition of the present invention, it is preferable that the mass ratio of the first liquid and the second liquid is substantially the same. 1:0.5 to 1:2, especially 1:0.75 to 1:1.25, further 1:0.9 to 1:1.1, especially 1:0.95 to 1:1.05 It is desirable to mix in a mass ratio of about.

In the composition of the present invention, the device for mixing the first liquid and the second liquid is not limited to static mixers such as static mixers, and known mixers such as planetary mixers and paddle mixers. machine.

The curing conditions for the composition of the present invention are not particularly limited, and may be the same as those for known addition reaction-curable silicone compositions. good. The curing conditions for heating may be 40 to 180° C. for 1 to 60 minutes.

The obtained cured product of the composition of the present invention preferably has a hardness in the range of 5 to 95, particularly 10 to 90, as determined by the Shore OO hardness tester specified in ASTM D 2240-05.

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, Vi represents a vinyl group and Me represents a methyl group.

（６）

（７）

（８）[Example 1-1]
In a 5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 100 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 600 mPa s, represented by the following general formula (6), and having a viscosity of 28 mPa at 25 ° C. 1.26 parts by mass of trimethylsiloxy group-blocked methylhydrogen dimethylpolysiloxane of s (SiH group in polysiloxane of formula (6)/SiVi group in dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 0 .11), 18 parts by mass of organopolysiloxane represented by the following general formula (7) and having a viscosity of 30 mPa s at 25 ° C., 60 ° C. x 24 hours, aluminum oxide powder is heated and extracted with pure water, and the water layer is The amount of Na ⁺ ions measured by ion chromatography is 22 ppm, and 600 parts by mass of molten spherical aluminum oxide A having an average particle size of 40 μm is heated and extracted with pure water at 60° C. for 24 hours, and the aqueous layer is obtained. When measured by ion chromatography, the amount of Na ⁺ ions was 3 ppm, and 400 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm was added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature, 9.4 parts by mass of dimethylhydrogensiloxy group-blocked dimethylpolysiloxane represented by the following general formula (8) and having a viscosity of 17 mPa s at 25 ° C. (SiH groups in polysiloxane of formula (8)/SiVi groups in dimethylpolysiloxane blocked at both molecular chain ends with dimethylvinylsiloxy groups = 0.79, total SiH in polysiloxanes of formulas (6) and (8) Group/SiVi group in dimethylpolysiloxane blocked at both ends of the molecular chain = 0.9), vinylsiloxane complex of chloroplatinic acid (Pt content: 1% by mass) 0.18 parts by mass, ethynylcyclohexanol 0 0.18 parts by mass were uniformly mixed to obtain a thermally conductive addition-curable silicone composition 1-1.

(6)

(7)

(8)

[Comparative Example 1-1]
Into a 5 L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 100 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 600 mPa s, represented by the above general formula (7), and having a viscosity of 30 mPa at 25 ° C. 18 parts by mass of organopolysiloxane of s, 600 parts by mass of molten spherical aluminum oxide A with an average particle size of 40 μm, and 400 parts by mass of crushed aluminum oxide B with an average particle size of 1.2 μm are added and mixed, and the mixture is heated to 150 ° C. Mixed time heat treatment.
Next, after sufficiently cooling this heat-treated mixture to room temperature, 1.26 parts by mass of trimethylsiloxy group-blocked methylhydrogen-dimethylpolysiloxane represented by the above general formula (6) and having a viscosity of 28 mPa s at 25 ° C. , 9.4 parts by mass of dimethylhydrogensiloxy group-blocked dimethylpolysiloxane represented by the above general formula (8) and having a viscosity of 17 mPa s at 25 ° C. (SiH groups in the polysiloxane of formula (6)/molecule SiVi groups in dimethylpolysiloxane blocked at both chain ends with dimethylvinylsiloxy groups = 0.11, SiH groups in polysiloxane of formula (8)/SiVi groups in dimethylpolysiloxane blocked at both molecular chain ends with dimethylvinylsiloxy groups = 0.79, total SiH groups in the polysiloxane of formulas (6) and (8)/SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain = 0.9), vinyl siloxane of chloroplatinic acid 0.18 parts by mass of the complex (Pt content: 1% by mass) and 0.18 parts by mass of ethynylcyclohexanol were uniformly mixed to obtain a thermally conductive addition-curable silicone composition 1-2.

[Comparative Example 1-2]
Thermally conductive addition-curable silicone composition 1-3 was obtained in the same manner as in Example 1-1, except that the heat treatment temperature was changed to 50°C.

[Comparative Example 1-3]
From the molten spherical aluminum oxide A described in Example 1-1, aluminum oxide powder was heated and extracted with pure water at 60° C. for 24 hours, and the water layer was measured by ion chromatography, and the amount of Na ⁺ ions was 55 ppm. Thermally conductive addition-curable silicone composition 1-4 was obtained in the same manner, except that fused spherical aluminum oxide C having an average particle size of 42 μm was used.

[Example 1-2]
In a 5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 100 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 400 mPa s, represented by the above general formula (6), and having a viscosity of 28 mPa at 25 ° C. 2.33 parts by mass of trimethylsiloxy group-blocked methylhydrogen dimethylpolysiloxane of s (SiH group in polysiloxane of formula (6)/SiVi group in dimethylpolysiloxane blocked at both molecular chain ends with dimethylvinylsiloxy group = 0 .15), 234 parts by mass of organopolysiloxane represented by the above general formula (7) and having a viscosity of 30 mPa s at 25 ° C., 60 ° C. x 24 hours, heat extraction of aluminum oxide powder with pure water, and the aqueous layer is The amount of Na ⁺ ions measured by ion chromatography is 11 ppm, and the average particle size is 58 μm. The molten spherical aluminum oxide D4, 836 parts by mass, is heated and extracted with pure water at 60 ° C. for 24 hours. The amount of Na ⁺ ions when the aqueous layer was measured by ion chromatography was 3 ppm, and 1,814 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 µm was added, mixed, and heated at 100 ° C. for 1 hour. Process mixed.
Next, after sufficiently cooling this heat-treated mixture to room temperature, 13.0 parts by mass of dimethylhydrogensiloxy group-blocked dimethylpolysiloxane represented by the above general formula (8) and having a viscosity of 17 mPa s at 25 ° C. (SiH groups in the polysiloxane of the formula (8)/SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain = 0.85, total SiH in the polysiloxanes of the formulas (6) and (8) Group/SiVi group in dimethylpolysiloxane blocked at both ends of the molecular chain = 1.0), vinylsiloxane complex of chloroplatinic acid (Pt content: 1% by mass) 1.00 parts by mass, ethynylcyclohexanol 1 00 parts by mass were uniformly mixed to obtain a thermally conductive addition-curable silicone composition 1-5.

[Comparative Example 1-4]
In a 5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 100 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 400 mPa s, represented by the above general formula (7), and having a viscosity of 30 mPa at 25 ° C. · 234 parts by mass of organopolysiloxane of s, heat extraction of aluminum oxide powder with pure water at 60 ° C. for 24 hours, and measure the water layer by ion chromatography The amount of Na ⁺ ions is 11 ppm, and the average particle size 836 parts by mass of molten spherical aluminum oxide D4 with a diameter of 58 μm, heat extraction of aluminum oxide powder with pure water at 60 ° C. for 24 hours, and measure the aqueous layer by ^ion chromatography. 1,814 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm was added and mixed, followed by heat treatment and mixing at 150° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature, 2.33 parts by mass of trimethylsiloxy group-blocked methylhydrogen-dimethylpolysiloxane represented by the above general formula (6) and having a viscosity of 28 mPa s at 25 ° C. , 13.0 parts by mass of dimethylhydrogensiloxy group-blocked dimethylpolysiloxane represented by the above general formula (8) and having a viscosity of 17 mPa s at 25 ° C. (SiH groups in the polysiloxane of formula (6)/molecule SiVi groups in dimethylpolysiloxane blocked at both chain ends with dimethylvinylsiloxy groups = 0.15, SiH groups in polysiloxane of formula (8)/SiVi groups in dimethylpolysiloxane blocked at both molecular chain ends with dimethylvinylsiloxy groups = 0.85, total SiH groups in polysiloxanes of formulas (6) and (8)/SiVi groups in dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 1.0), vinyl siloxane of chloroplatinic acid 1.00 parts by mass of the complex (Pt content: 1% by mass) and 1.00 parts by mass of ethynylcyclohexanol were uniformly mixed to obtain a thermally conductive addition-curable silicone composition 1-6.

[Comparative Example 1-5]
Thermally conductive addition-curable silicone composition 1-7 was obtained in the same manner as in Example 1-2, except that the heat treatment temperature was changed to 50°C.

The viscosities of the thermally conductive addition-curable silicone compositions 1-1 to 1-7 described in Examples 1-1 and 1-2 and Comparative Examples 1-1 to 1-5 were measured using a spiral viscometer: a Malcolm viscometer. (Type PC-10AA, rotation speed 10 rpm) was measured in a 25 ° C. environment, and the thermal conductivity was measured using a hot disk method thermophysical property measurement device TPS 2500 S manufactured by Kyoto Electronics Industry Co., Ltd. Each silicone at 25 ° C. The thermal conductivity of the composition before curing was measured (hot disc method according to ISO 22007-2).
After that, it is sufficiently vacuum degassed and poured into a mold having a cured thickness of 6 mm, heated and cured at 120 ° C. for 60 minutes to obtain a cured product, and its hardness is Shore OO hardness specified in ASTM D 2240-05. measured by a meter. After leaving each of these compositions in a refrigerator at 5° C. for 6 months, the viscosity, thermal conductivity and hardness were measured in the same manner as above, and the results are shown in Tables 1 and 2 in comparison with the initial results.

As is clear from the above results, the presence or absence of component (B), a treatment agent capable of treating the surface of the thermally conductive filler when stored for a long period of time, showed no significant change in viscosity or thermal conductivity, but the hardness A large change of 10 points or more is observed over time from the initial stage. Also, it can be seen that the amount of Na ⁺ ions defined in component (C) is preferably 50 ppm or less. Furthermore, it can be seen that the heat treatment temperature is preferably 70° C. or higher after mixing the components (A), (B) and (C). Therefore, according to the present invention, a thermally conductive addition-curable silicone composition having long-term storage stability and a cured product thereof can be obtained.

（６）

（７）

（８）[Example 2-1]
In a 5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 55.2 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 600 mPa s, and a viscosity at 25 ° C. represented by the following general formula (7) 9 parts by mass of organopolysiloxane having a viscosity of 30 mPa s, aluminum oxide powder is heated and extracted with pure water at 60 ° C. for 24 hours, and the water layer ^is measured by ion chromatography. Aluminum oxide powder was heated and extracted with 300 parts by mass of molten spherical aluminum oxide A having a particle size of 40 μm and pure water at 60° C. for 24 hours, and the ^aqueous layer was measured by ion chromatography. , and 200 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm were added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25° C.), 0.18 parts by mass of a vinylsiloxane complex of chloroplatinic acid (Pt content: 1% by mass) was uniformly mixed at room temperature (25° C.) for 20 minutes. to obtain a thermally conductive addition-curable silicone composition 2-1 (first liquid).
In a 5 L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 44.8 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 600 mPa s, and a viscosity at 25 ° C. represented by the following general formula (6) 1.26 parts by mass of trimethylsiloxy-group-blocked methylhydrogen-dimethylpolysiloxane (SiH group in polysiloxane of formula (6)/total SiVi group = 0.11), 9 parts by mass of an organopolysiloxane represented by the following general formula (7) and having a viscosity of 30 mPa s at 25 ° C., 60 ° C. × 24 hours, heat extraction of aluminum oxide powder with pure water, The amount of Na ⁺ ions when the water layer was measured by ion chromatography was 22 ppm, and 300 parts by mass of molten spherical aluminum oxide A having an average particle size of 40 µm was heated at 60°C for 24 hours with pure water to extract the aluminum oxide powder. , The amount of Na ⁺ ions when the water layer was measured by ion chromatography was 3 ppm, and 200 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 µm was added and mixed, and the mixture was heated at 100°C for 1 hour. Mixed with heat treatment.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25° C.), 0.02 parts by mass of ethynylcyclohexanol and dimethyl represented by the following general formula (8) and having a viscosity of 17 mPa s at 25° C. Hydrogensiloxy group-blocked dimethylpolysiloxane 9.4 parts by mass (SiH groups in the polysiloxane of formula (8)/total SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain = 0.79, formula The total SiH groups in the polysiloxane of (6) and (8)/SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 0.9) were uniformly mixed at room temperature (25°C) for 20 minutes. to obtain a thermally conductive addition-curable silicone composition 2-1 (liquid 2).

(6)

(7)

(8)

[Comparative Example 2-1]
In a 5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 55.2 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 600 mPa s, and the viscosity at 25 ° C. represented by the general formula (7) 9 parts by mass of organopolysiloxane having a viscosity of 30 mPa s, aluminum oxide powder is heated and extracted with pure water at 60 ° C. for 24 hours, and ^the water layer is measured by ion chromatography. Aluminum oxide powder was heated and extracted with 300 parts by mass of molten spherical aluminum oxide A having a particle size of 40 μm and pure water at 60° C. for 24 hours, and the ^aqueous layer was measured by ion chromatography. , and 200 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm were added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25° C.), 0.18 parts by mass of a vinylsiloxane complex of chloroplatinic acid (Pt content: 1% by mass) was uniformly mixed at room temperature (25° C.) for 20 minutes. to obtain a thermally conductive addition-curable silicone composition 2-2 (first liquid).
In a 5 L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 44.8 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 600 mPa s, the viscosity at 25 ° C. represented by the above general formula (7) 9 parts by mass of organopolysiloxane having a viscosity of 30 mPa s, aluminum oxide powder is heated and extracted with pure water at 60 ° C. for 24 hours, and ^the water layer is measured by ion chromatography. Aluminum oxide powder was heated and extracted with 300 parts by mass of molten spherical aluminum oxide A having a particle size of 40 μm and pure water at 60° C. for 24 hours, and the ^aqueous layer was measured by ion chromatography. , and 200 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm were added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25° C.), 0.02 parts by mass of ethynylcyclohexanol, trimethylsiloxy group-blocking represented by the above general formula (6) and having a viscosity of 28 mPa s at 25° C. 1.26 parts by mass of methylhydrogen-dimethylpolysiloxane (SiH groups in the polysiloxane of the formula (6)/total SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 0.11); 9.4 parts by mass of dimethylhydrogensiloxy group-blocked dimethylpolysiloxane represented by the general formula (8) and having a viscosity of 17 mPa s at 25 ° C. (SiH groups in the polysiloxane of formula (8) / the above molecular chain Total SiVi groups in dimethylpolysiloxane blocked at both ends with dimethylvinylsiloxy groups = 0.79, total SiH groups in polysiloxanes of formulas (6) and (8)/dimethylpolysiloxane blocked with dimethylvinylsiloxy groups at both ends of the above molecular chain (SiVi groups in the mixture = 0.9) were uniformly mixed at room temperature (25°C) for 20 minutes to obtain a thermally conductive addition-curable silicone composition 2-2 (liquid 2).

[Comparative Example 2-2]
Thermally conductive addition-curable silicone composition 2-3 (first liquid/second liquid) was obtained in the same manner as in Example 2-1, except that the heat treatment temperature was changed to 50°C.

[Comparative Example 2-3]
Aluminum oxide powder was heated and extracted with pure water at 60° C. for 24 hours from the molten spherical aluminum oxide A described in Example 2-1, and the aqueous layer was measured by ion chromatography, and the amount of Na ⁺ ions was 55 ppm. A thermally conductive addition-curable silicone composition 2-4 (first liquid/second liquid) was obtained in the same manner, except that fused spherical aluminum oxide C having an average particle size of 42 μm was substituted.

[Example 2-2]
In a 5 L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 57.2 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 400 mPa s, the viscosity at 25 ° C. represented by the general formula (7) 117 parts by mass of organopolysiloxane with a viscosity of 30 mPa s, aluminum oxide powder is heated and extracted with pure water at 60 ° C. for 24 hours, and the ^aqueous layer is measured by ion chromatography. 2,418 parts by mass of molten spherical aluminum oxide D with a particle size of 56 μm, heat extraction of aluminum oxide powder with pure water at 60 ° C. for 24 hours, and measure the aqueous layer by ion chromatography. The amount of Na ⁺ ions is 3 ppm. 907 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm was added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25°C), 1.00 parts by mass of a vinylsiloxane complex of chloroplatinic acid (Pt content: 1% by mass) was uniformly mixed at room temperature (25°C) for 20 minutes. to obtain a thermally conductive addition-curable silicone composition 2-5 (first liquid).
In a 5L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 42.8 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 400 mPa s, the viscosity at 25 ° C. 2.33 parts by mass of trimethylsiloxy-group-blocked methylhydrogen-dimethylpolysiloxane (SiH group in polysiloxane of formula (6)/total SiVi in dimethylvinylsiloxy-group-blocked dimethylpolysiloxane at both molecular chain ends group = 0.15), 117 parts by mass of organopolysiloxane represented by the above general formula (7) and having a viscosity of 30 mPa s at 25 ° C., 60 ° C. x 24 hours Heat extraction of aluminum oxide powder with pure water, 2,418 parts by mass of molten spherical aluminum oxide D having an average particle size of 56 μm and an Na ⁺ ion content of 22 ppm when the aqueous layer was measured by ion chromatography, and aluminum oxide powder was heated with pure water at 60° C. for 24 hours. Extract, the amount of Na ⁺ ions when the aqueous layer is measured by ion chromatography is 3 ppm, and 907 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm is added and mixed, and heated at 100 ° C. Heat treated and mixed for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25° C.), 0.11 parts by mass of ethynylcyclohexanol and dimethyl represented by the general formula (8) and having a viscosity of 17 mPa s at 25° C. Hydrogensiloxy group-blocked dimethylpolysiloxane 13.0 parts by mass (SiH groups in polysiloxane of formula (8)/total SiVi groups in dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 0.85, formula The total SiH groups in the polysiloxane of (6) and (8)/SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 1.0) were uniformly mixed at room temperature (25°C) for 20 minutes. to obtain a thermally conductive addition-curable silicone composition 2-5 (second liquid).

[Comparative Example 2-4]
In a 5 L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 57.2 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 400 mPa s, the viscosity at 25 ° C. represented by the general formula (7) 117 parts by mass of organopolysiloxane with a viscosity of 30 mPa s, aluminum oxide powder is heated and extracted with pure water at 60 ° C. for 24 hours, and the ^aqueous layer is measured by ion chromatography. 2,418 parts by mass of molten spherical aluminum oxide D with a particle size of 56 μm, heat extraction of aluminum oxide powder with pure water at 60 ° C. for 24 hours, and measure the aqueous layer by ion chromatography. The amount of Na ⁺ ions is 3 ppm. 907 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm was added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25°C), 1.00 parts by mass of a vinylsiloxane complex of chloroplatinic acid (Pt content: 1% by mass) was uniformly mixed at room temperature (25°C) for 20 minutes. to obtain a thermally conductive addition-curable silicone composition 2-6 (first liquid).
In a 5 L planetary mixer manufactured by Inoue Seisakusho Co., Ltd., 42.8 parts by mass of dimethylpolysiloxane having both molecular chain ends blocked with dimethylvinylsiloxy groups having a viscosity of 400 mPa s, the viscosity at 25 ° C. 117 parts by mass of organopolysiloxane with a viscosity of 30 mPa s, aluminum oxide powder is heated and extracted with pure water at 60 ° C. for 24 hours, and the ^aqueous layer is measured by ion chromatography. 2,418 parts by mass of molten spherical aluminum oxide D with a particle size of 56 μm, heat extraction of aluminum oxide powder with pure water at 60 ° C. for 24 hours, and measure the aqueous layer by ion chromatography. The amount of Na ⁺ ions is 3 ppm. 907 parts by mass of crushed aluminum oxide B having an average particle size of 1.2 μm was added and mixed, followed by heat treatment and mixing at 100° C. for 1 hour.
Next, after sufficiently cooling this heat-treated mixture to room temperature (25° C.), 0.11 parts by mass of ethynylcyclohexanol and trimethylsiloxy group-blocked solution having a viscosity of 28 mPa s at 25° C. represented by the above general formula (6) 2.33 parts by mass of methylhydrogen-dimethylpolysiloxane (SiH groups in the polysiloxane of the formula (6)/total SiVi groups in the dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both molecular chain ends = 0.15); 13.0 parts by mass of dimethylhydrogensiloxy group-blocked dimethylpolysiloxane represented by the general formula (8) and having a viscosity of 17 mPa s at 25° C. (SiH groups in the polysiloxane of formula (8)/the molecular chain Total SiVi groups in dimethylpolysiloxane blocked at both ends with dimethylvinylsiloxy groups = 0.85, total SiH groups in polysiloxanes of formulas (6) and (8)/dimethylpolysiloxane blocked with dimethylvinylsiloxy groups at both ends of the above molecular chain (SiVi groups in the mixture = 1.0) were uniformly mixed at room temperature (25°C) for 20 minutes to obtain a thermally conductive addition-curable silicone composition 2-6 (liquid 2).

[Comparative Example 2-5]
Thermally conductive addition-curable silicone composition 2-7 (first liquid/second liquid) was obtained in the same manner as in Example 2-2, except that the heat treatment temperature was changed to 50°C.

Thermally conductive addition-curable silicone compositions 2-1 (first liquid/second liquid) to 2-7 (second liquid) described in Examples 2-1 and 2-2 and Comparative Examples 2-1 to 2-5 above Liquid 1/Liquid 2) is measured using a spiral viscometer: Malcolm viscometer (type PC-10AA, rotation speed 10 rpm) at 25 ° C. Thermal conductivity is manufactured by Kyoto Electronics Industry Co., Ltd. The thermal conductivity of each silicone composition before curing was measured at 25° C. using a hot disk method thermophysical property measuring device TPS 2500 S (hot disk method in accordance with ISO 22007-2).

After that, using a static mixer (MXA6.3-21) manufactured by Noritake Co., Ltd., the first liquid and the second liquid of each composition were mixed at room temperature (mass ratio of 1:1) so that they were uniform. After mixing and discharging at 25 ° C.), it is sufficiently vacuum degassed, poured into a mold having a cured thickness of 6 mm, cured at 25 ° C. for 24 hours to obtain a cured product, and its hardness (hardness) is measured according to ASTM D 2240. Measured with a Shore OO hardness tester specified in -05. In addition, after leaving the first liquid and the second liquid of each of these compositions in a constant temperature bath at 25 ° C. for 6 months, the viscosity, thermal conductivity, and hardness were measured in the same manner as above, and the results were compared with the initial results. Shown in Tables 3 and 4.

As is clear from the above results, the compositions of Examples 2-1 and 2-2 of the present invention show no change in viscosity or thermal conductivity even after long-term storage (25° C., 6 months). No change in the hardness of the resulting cured product was observed, while the compositions of Comparative Examples 2-1 to 2-5 showed no significant change in viscosity or thermal conductivity after long-term storage. It can be seen that the hardness of the cured product changed by 10 points or more from the initial stage. Thus, from Comparative Examples 2-1 and 2-4, it can be seen that it is preferable to heat and mix component (B) with components (A) and (C) as the second liquid. Also, from Comparative Example 2-3, it can be seen that the amount of Na ⁺ ions defined in component (C) is preferably 50 ppm or less. Furthermore, from Comparative Examples 2-2 and 2-5, it can be seen that the heat treatment temperature is preferably 70° C. or higher after mixing the components (A), (B), and (C) as the second liquid. . Therefore, according to the present invention, a thermally conductive addition-curable silicone composition having long-term storage stability and a cured product thereof can be obtained.

The thermally conductive silicone cured product obtained by curing the thermally conductive addition-curable silicone composition obtained according to the present invention is stable without being affected by the thermally conductive filler even after long-term storage. Since the hardness can be maintained, improvement in reliability is expected in applications for heat dissipation and protection of electronic parts such as power devices, transistors, thyristors, and CPUs (central processing units).

Claims (12)

(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane represented by and having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (B) ( SiH group) is 0.1 to 2,
(C) Aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60°C for 24 hours and the water layer is measured by ion chromatography: 1,000 to 7,000 mass a heat-treated mixture having a temperature of 70° C. or higher in the part, wherein the aluminum oxide particles are surface-treated with the organohydrogenpolysiloxane;
(D) the following average composition formula (3)
^R3eHfSiO _{(4-ef)/2 ( 3} )
(wherein R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, e is 0.7 to 2.2, f is 0.001 to 0.5 and e+f is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (D) ( SiH group) is 0.01 to 3, and (E) platinum group metal catalyst: 1 to 200 ppm in terms of mass of platinum group metal relative to component (A)
In the hot disk method in accordance with ISO 22007-2, the thermal conductivity of the composition is 2.0 to 7.0 W / m K, and the viscosity of the composition at 25 ° C. is determined by a spiral viscometer. 2. The thermally conductive addition-curable silicone composition according to claim 1, which has a viscosity of 30 to 800 Pa·s when measured at a rotational speed of 10 rpm (shear rate of 6 (1/sec)). The thermal conductivity according to claim 1 , wherein the total amount of SiH groups in components (B) and (D) is 0.11 to 5 per alkenyl group in component (A). Addition-curable silicone composition. The heat-treated mixture contains components (A) to (C), a silane coupling agent (F) and/or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
The thermally conductive addition-curable silicone according to claim 1 or 2, which is a heat-treated mixture at a temperature of 70°C or higher with an organopolysiloxane (G) having a viscosity of 0.01 to 30 Pa s at 25°C. Composition. (A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane represented by and having at least two alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass,
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (B) ( SiH group) is 0.1 to 2,
(C) Aluminum oxide having a Na ⁺ ion content of 50 ppm or less when the aluminum oxide powder is heated and extracted with pure water at 60°C for 24 hours and the water layer is measured by ion chromatography: 1,000 to 7,000 mass Part is heat-treated at a temperature of 70 ° C. or higher, and the cooled heat-treated mixture is
(D) the following average composition formula (3)
^R3eHfSiO _{(4-ef)/2 ( 3} )
(wherein R ³ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, e is 0.7 to 2.2, f is 0.001 to 0.5 and e+f is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule: for each alkenyl group in component (A), a silicon-bonded hydrogen atom in component (D) ( SiH group) is 0.01 to 3, and (E) platinum group metal catalyst: 1 to 200 ppm in terms of mass of platinum group metal relative to component (A)
By adding and mixing, the thermal conductivity of the resulting composition is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the viscosity of the resulting composition at 25 ° C. is 30 to 800 Pa·s when measured with a spiral viscometer at a rotor A rotation speed of 10 rpm (shear rate 6 (1/sec)). The thermal conductivity according to claim 4 , wherein the total amount of SiH groups in components (B) and (D) is 0.11 to 5 per alkenyl group in component (A). A method for producing an addition-curable silicone composition. In addition to components (A) to (C), a silane coupling agent (F) and / or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
and having a viscosity of 0.01 to 30 Pa·s at 25° C. is mixed with the organopolysiloxane (G) and heat-treated. Method. (A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
and (C) heat-extracting aluminum oxide powder with pure water at 60° C. for 24 hours, and subjecting the water layer to ion chromatography. a heat-treated mixture at a temperature of 70° C. or higher of aluminum oxide having a Na ⁺ ion content of 50 ppm or less as measured graphically;
(E) a platinum group metal catalyst: a first liquid containing 1 to 200 ppm by mass of platinum group metal relative to the total mass of component (A);
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, represented by
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms per molecule represented by the formula: Silicon-bonded hydrogen in component (B) per alkenyl group in the total of component (A) and (C) the Na ⁺ obtained by heat-extracting the aluminum oxide powder with pure water at 60° C. for 24 hours and measuring the water layer by ion chromatography. a heat-treated mixture of aluminum oxide having an ion content of 50 ppm or less at a temperature of 70° C. or higher, wherein the aluminum oxide particles are surface-treated with the organohydrogenpolysiloxane;
(H) Average composition formula (4) below
^R7jHkSiO ₍ 4 _{- jk)/2} (4)
(wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, j is 0.7 to 2.2, k is 0.001 to 0.5 and j+k is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having two silicon-bonded hydrogen atoms in one molecule represented by: per alkenyl group in the total of component (A), a silicon-bonded hydrogen atom in component (H) (SiH groups) in an amount of 0.01 to 3, and a second liquid containing 0.01 to 3 groups, provided that the first liquid does not contain the above components (B) and (H), and the second liquid does not contain the above components (B) and (H). Liquid 2 does not contain the above component (E), the total amount of component (A) in the composition is 100 parts by mass, the total amount of component (C) is 1,000 to 7,000 parts by mass, The thermal conductivity of each of liquid 1 and liquid 2 is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the viscosity of each liquid 1 and 2 at 25 ° C. is 30 to 800 Pa·s when measured with a spiral viscometer at a rotor A rotation speed of 10 rpm (shear rate 6 (1/sec)). The heat according to claim 7 , wherein the total amount of SiH groups in components (B) and (H) is 0.11 to 5 per alkenyl group in the total amount of component (A). A conductive addition-curable silicone composition. Furthermore, a silane coupling agent (F) and / or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
represented by, and the viscosity at 25 ° C. of 0.01 ~ 30 Pa s organopolysiloxane (G), the first component (A), (C) as a heat-treated mixture at a temperature of 70 ° C. or higher with the first component, the second 9. The thermally conductive addition-curable silicone composition according to claim 7 or 8 , which is contained in the two components as a heat-treated mixture with components (A), (B), and (C) at a temperature of 70°C or higher. (A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
and (C) heat-extracting aluminum oxide powder with pure water at 60° C. for 24 hours, and subjecting the water layer to ion chromatography. Aluminum oxide having an amount of Na ⁺ ions of 50 ppm or less as measured graphically is mixed at a temperature of 70° C. or higher and heat-treated, and the cooled heat-treated mixture is mixed with
(E) platinum group metal catalyst: 1 to 200 ppm in platinum group metal mass with respect to the total mass of component (A)
A step of preparing the first liquid by adding and mixing
(A) the following average composition formula (1)
_{RaR1bSiO (} 4- ^ab _)/2 (1)
(wherein R is independently an alkenyl group, R ¹ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, a is 0.0001 to 0.2, b is a positive number that satisfies 1.7 to 2.2 and a+b satisfies 1.9 to 2.4.)
Organopolysiloxane having at least two alkenyl groups bonded to silicon atoms in one molecule, represented by
(B) the following average composition formula (2)
^R2cHdSiO _{( 4-cd)/2 (} 2)
(wherein R ² is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, c is 0.7 to 2.2, d is 0.001 to 0.5 and c+d is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having at least 3 silicon-bonded hydrogen atoms per molecule represented by the formula: Silicon-bonded hydrogen in component (B) per alkenyl group in the total of component (A) and (C) the Na ⁺ obtained by heat-extracting the aluminum oxide powder with pure water at 60° C. for 24 hours and measuring the water layer by ion chromatography. Aluminum oxide having an ion amount of 50 ppm or less is mixed at a temperature of 70 ° C. or higher and heat-treated, and the cooled heat-treated mixture is
(H) Average composition formula (4) below
^R7jHkSiO ₍ 4 _{- jk)/2} (4)
(wherein R ⁷ is independently an unsubstituted or substituted monovalent hydrocarbon group having no aliphatic unsaturated bond, j is 0.7 to 2.2, k is 0.001 to 0.5 and j+k is a positive number that satisfies 0.8 to 2.5.)
Organohydrogenpolysiloxane having two silicon-bonded hydrogen atoms in one molecule represented by the formula: per one alkenyl group in the total of component (A), a silicon-bonded hydrogen atom in component (H) (SiH group) is mixed in an amount of 0.01 to 3 to prepare a second liquid, provided that the first liquid contains the components (B) and (H), the second liquid does not contain the (E) component, the total of the (A) component in the composition is 100 parts by mass, the total of the (C) component is 1,000 to 7,000 parts by mass, and obtained The thermal conductivity of each of the first and second liquids is 2.0 to 7.0 W / m K in the hot disk method in accordance with ISO 22007-2, and the obtained first and second liquids each have a thermal conductivity of 25 A method for producing a thermally conductive addition-curable silicone composition having a viscosity of 30 to 800 Pa·s at °C when measured with a spiral viscometer at a rotor A rotation speed of 10 rpm (shear rate 6 (1/sec)). The heat according to claim 10 , wherein the total amount of SiH groups in components (B) and (H) is 0.11 to 5 per alkenyl group in the total of components (A). A method for producing a conductive addition-curable silicone composition. Furthermore, a silane coupling agent (F) and / or the following general formula (5)

(5)
(wherein R ⁴ is independently an unsubstituted or substituted monovalent hydrocarbon group; R ⁵ is independently an alkyl group, alkoxyalkyl group, alkenyl group or acyl group; g is an integer of 5 to 100; Yes, and h is an integer from 1 to 3.)
and an organopolysiloxane (G) having a viscosity of 0.01 to 30 Pa s at 25 ° C., components (A) and (C) of the first liquid, and components (A) and (B) of the second liquid. 12. The method for producing a thermally conductive addition-curable silicone composition according to claim 10 or 11, wherein the composition is mixed with component (C) and heat-treated.